RBMHHB 


THE  CLAY  RESOURCES  AND 

THE  CERAMIC  INDUSTRY 

OF  CALIFORNIA 


BY 

WALDEMAR  FENN  DIETRICH 


BULLETIN  No,  99 


ISSUED  BY  THE 

CALIFORNIA  STATE  MINING  BUREi^n 

FERRY  BUiLDLNG.  SAN  FRANCISCO 


1928 


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THE  LIBRARY 

OF 

THE  UNIVERSITY 

OF  CALIFORNIA 

DAVIS 


Photo   No    1.     Russ    Building.    San    Francisoo,    faced    with    architectural    terra    cotta 

throu^lTthron^\''''  'f  \?'"  '"""'  °'  Gladding.  McBean  &  Co.      (Photo  supplied 
tniougii  the  courtesy  of  the  company.) 


54979 


STATE  OF  CALIFORNIA 

DEPARTMENT  OF  NATl RAL  RESOURCES 

FRED  G.  STEVENOT,  I)ir.-.t..r 

DIVISION  OF  MINES  AND  MINING 

FERRY  BUILWNG,  SAN  FRANCISCO 
LLOYD  L.  ROOT  State  Mineralogist 

San  Francisco]  BULLETIN  No.  99  [January,  1928 


The  Clay  Resources  and  the 

Ceramic  Industry  of 

Gahfornia 


By 
WALDEMAR  FENN  DIETRICH 

Associate  Professor  of  Mining  Engineer- 
ing, Stanford  University 


CALIFORNIA   STATE   PRINTING   OFFICE 
SACRAMENTO,  192  8 


LIBRARY 

UNIVERSliY  OF  CALIFORNIA 
DAVIS 


CONTENTS. 


Page 

Letter  of  transmittal 10 

Chapter   I,   Introduction 11 

Methods  of  investigation 12 

Previous   work    12 

Acknowledgments    13 

General  references  13 

Chapter  II,  Summary  of  the  ceramic  industry  of  California 15 

Introduction 15 

Definition  of  clay 15 

Kaolin 15 

China  clay 15 

Ball  clay 15 

Fireclay    15 

Pace   brick   clay 15 

Common  brick  clay 15 

Slip    clay    15 

Clay  preparation   15 

Manufacturing   processes   Ifi 

Shaping     16 

Drying     17 

Firing    17 

Glazing 17 

Clay  deposits  of  California 17 

Mining  methods   20 

Ceramic  plants 21 

Manufacturing  methods  in  California  plants 26 

Common   brick     26 

Hollow  brick 26 

Face  brick 26 

Sewer  pipe 26 

" ^  Drain    tile    26 

Terra  cotta   26 

Conduits      27 

• Roofing   tile    27 

Flue    lining    28 

-Floor  tile 28 

—~Wall  and  fireplace  tile 28 

Refractories     29 

Tableware    30 

Kitchen  w-are  and  stoneware 30 

Art   pottery    30 

Red  earthenware   30 

Sanitary    ware    30 

Electrical    insulators    30 

Thermal    insulators    30 

Statistics    31 

.iw^— '  Brick  and  hollow  tile 31 

Pottery    clay    31 

Total  annual  value  of  clay  products  in  California  compared  to  the  total 

for  the  United  States 35 

Chaiiter  III,  Clay  deposits  and  ceramic  plants  by  counties 38 

Alameda    County    38 

Amador   County   49 

Butte   County    64 

Calaveras    County    67 

Colusa   County    70 

Contra  Costa  County "1 

Del   Norte   County   77 

Fresno  County   77 

Glenn   Countv 79 

Humboldt   County    79 

Imperial    County    83 

Inyo   County    87 

Kern    County     88 

Kings  County 90 

Lake  County 91 

Lassen   County   92 

Los  Angeles  County 92 

Madera    County    123 

Marin  County   123 

Mendocino    County     126 

Merced  County 127 

Monterey  County 129 

Napa    County 132 

Nevada   County    '. 135 

Orange  County 139 

Placer    County    ; 146 

Riverside  County 161 

Sacramento  Countv 182 

San  Benito   County   190 


9^*^11 


b  CONTENTS 

Page 

San  Bernardino    County    193 

San   Diego  County   19S 

San   Francisco   County   206 

San  Joaquin    County    207 

San  Luis  Obispo  County 212 

San   Mateo    County    215 

Santa   Barbara    County    217 

Santa  Clara   County   219 

Santa  Cruz  County 222 

Shasta   County    222 

Siskiyou    Countv    224 

Solano    County    225 

Sonoma    County    225 

Stanislaus  County   228 

Sutter    County    230 

Tehama   County    230 

Tulare    County    231 

Ventura  County 233 

Yolo   County    234 

Yuba    County    235 

Chapter  IV,  Clay  tests  and  their  interpretation  and  the  classification  of  clays 237 

Field  tests 237 

Laboratory   tests    238 

Preparation  of  samples 238 

Test  pieces 239 

Drying    239 

Plastic  and   drying  properties   239 

Plasticity    239 

Water  of  plasticity 239 

Shrinkage   water    240 

Pore    \vater    240 

Shrinkage     240 

Dry   transverse   strength    240 

Bonding  strength 241 

Fineness    241 

Firing  properties 242 

Firing  treatment    242 

Pyrometric    control    243 

Firing   shrinkage    245 

Absorption 245 

Apparent   porosity    245 

Apparent  specific  gravity 245 

Apparent   density   24(J 

True  specific  gravity 246 

Softening    i^oint    246 

■ Texture,  structure  and  hardness 248 

Color     248 

Ridgway  color  standards 249 

Munsell  color  standards 250 

Ridgway   vs.   Munsell   250 

Color  classification  of  clays 251 

Chemical   analysis    252 

Classification   of  clays 253 

Chapter  V,  Results  of  laboratory  tests 257 

I.  White-  or  cream-burning  non-calcareous  clays 257 

A.  Open-burning    257 

1.  Low    strength    257 

2.  Medium  to  high  strength 264 

B.  Dense-burning  between  cones  10  and  15 272 

3.  Generally  refractory 272 

C.  Dense-burning  between  cones  5  and  10 273 

4.  Generally  refractory 273 

II.   Buff-burning   clays    277 

A.  Refractory  clays 277 

a.  Open-burning     277 

5.  Low  strength 277 

6.  Medium  to  high   strength 287 

b.  Dense-burning  between  cones  10  and  15 296 

7.  Mainly  medium  to  high  strength 296 

c.  Dense-burning  between  cones  5  and  10 302 

8.  Medium   to  high   strength 302 

B.  Non-refractory  clays   311 

a.  Open-burning    311 

9.   Medium   to  high   strength 311 

10.  Low  strength 314 

b.  Dense-burning     316 

11.  Low  strength 316 

ITT.  Red-burning  clays 321 

A.  Open-burning 321 

12.  Medium   to   high   strength 321 

13.  Low    strength    328 

B.  Dense-burning    334 

a.   With  long  vitrification  range 334 

14.   Mainly  medium  to  high  strength 334 


CONTENTS  7 

I'age 

b.   With   short   vitrification   range :. 338 

ir>.   M.dium    to   high   strength 338 

IV.   Clays  liiirning  dirty  white,  cream  white  or  yellowish  white 348 

17.   Cenorally  contain  calcium   or   magnesium   carbonate 348 

Chemical  analyses 353 

Index  of  clay  sample   numbers   357 

Index  of  clay  samples,  by  counties 358 

General  index - 362 


LIST  OF  TABLES. 


No.  Title  rage 

1.  Check  list  of  ceramic  plants   In   California 22-  25 

—  2.  Brick  and  hollow  tile  production  for  llt26,  l)y  counties 32 

.').  Common  brick  production  (jf  California,  l).v  years 33 

4.  Production  of  pottery  clay   in   California   in    1926 33 

5.  Pottery  clay  production  of  California,  l>y  years 34 

6.  Value  of  pottery  clay  products  made  in  California  during  l!t2i) 34 

7.  California  and  total  United  States  production  of  ceramic  products  from  1896 

to    192C    36 

8.  Description  of  core  drill  samples  from  lone  district 52 

!t.  End  points  of  Orton  pyrometric  cones  m  Centigrade  and  Fahrenheit  degrees.  244 

10.  Visual  correlation  of  certain  Ridgway  colors  with  Munsell  colors 251 

11.  Key  to  classification  of  clay  samples  tested 258 

12.  Drying  data,  clays  of  classes   1  and   2 267 

13.  Firing    data,   clays  of  classes   1   and   2 268 

14.  Drying  data,  clays  of  classes  3  and   4 274 

15.  Firing    data,   clays  of  classes   3   and   4 275 

Hi.  Drying  data,   clays  of  class   5 283 

17.  Firing    data,   clays  of  class   5   284 

18.  Drying  data,  clays  of  class  6 293 

19.  Firing    data,   clays  of  class   6 294 

20.  Drying  data,  clays  of  classes   7  and   8 306 

21.  Firing    data,  clays  of  classes   7  and   8 307 

22.  Drving  data,  clays  of  classes  9,   10  and   11    317 

23.  Firing    data,  clays  of  clas.ses  9,   10  and   11    318 

24.  Drying  data,   clays  of  clas.ses   12   and   13     ^''Q 

25.  Firing    data,  clays  of  classes   12  and   13     33i 

26.  Drying  data,   clays  of  classes   14   and   15     : 344 

27.  Firing    data,   clays  of  classes   14   and   15     345 

28.  Drying  data,   clays  of  cla.ss    17 350 

29.  Firing    data,   clays  of  class   17   351 

30.  Chemical   analyses  of  clays  from   sampled   deposits 354-355 

31.  Chemical  analyses  of  miscellaneous  California  clays,  not  sampled 356 


LIST  OF  PLATES. 


No.  Title                                                                                                                   Page 

I.   Map  showing  locations  of  high-grade  clay  deposits  in  California IS 

II.   Common  brick  and  cement  statistics  of  California 33 

TIT.   Annual  value  of  clay  jiroducts  in  California  and  in  the  United  States 37 

IV.   Map  of  Tesla  district,  Alameda   County 43 

V.   Ceologic  section  through  main  Tesla  shaft 44 

VI.    Property  map  of  If)ne  district,   Amador  County 50 

VIT.    Sketch  mai)  of  Clark  and  Marsh  kaolin  mine  near  Calistoga 134 

VIII.  (ieneral  arrangement  of  (piarry  and  plant  of  the  Clay  Corporation  of  Cali- 
fornia,   Lincoln,    Placer   County 148 

IX.  Vertical  section  of  clay  beds  on  Clay  Corporation  of  California's  jiroperty, 

near  Lincoln   149 

X.  Property  map  of  Alberhill-Corona  district.  Riverside  County 162 

XT.   Diagrammatic  section  of  strata  at  Alberhill 163 

XII.   Handling  and  storage  of  clay  by  the  "glory-hole"  method 168 


LIST  OF  PHOTOS. 


No.  Title  Page 

1.  Russ   Building,    San    Francisco Frontispiece 

2.  Ryan  Ranch  clay  deposit 46 

3.  Filter-press  room,  Westinghouse  Electric  and  Manufacturing  Company 47 

4.  Hot-pressing  room,  Westinghouse  Electric  and  Manufacturing  Company 48 


b  CONTENTS 

Page 

5.  Gage  clay  pit 53 

6.  Jones  Butte  Mine 54 

7.  Barber  or  Shepard  pit 55 

8.  Sand  Pit  subleased  by  the  lone  Fire  Brick  Company 55 

9.  Yaru  clay  pit 56 

10-A.   Fancher   clay   pit    59 

10-B.   Brick  machinery  in  plant  of  lone  Fire  Brick  Company 60 

10-C.    Sand  pit  of  the  lone  Fire  Brick  Company 62 

11.  Valley  Springs  clay  pit 69 

12.  California  Art  Tile  Company's  ijlant 72 

13.  Richmond   Pressed  Brick  Company's  plant 75 

14.  Plant   of  Thompson   Brick  Company 82 

15.  Vitrefrax    cvanite    deposit    86 

16.  Malibu    Pottery    106 

17.  Drying  floor,  Los  Nietos  plant  of  Pacific  Clay  Products  Company 108 

18.  Airplane  view,  Lincoln  Heights  plant,  Pacific  Clay  Products  Comjjany 110 

19.  Airplane  view,  Los  Nietos  plant,   Pacific  Clay  Products  Company 112 

20.  Clay  bins  and  unloading  crane,  Lincoln  Heights  plant.  Pacific  Clay  Products 

Company,    Los   Angeles 113 

21.  Pug-mill,    auger    machine    and    cutter,    Lincoln    Heights    plant.    Pacific    Clay 

Products  Company,   Los   Angeles   114 

22.  Dry  pans  and  twin  wet  pans,  Los  Nietos  plant,  Pacific  Clay  Products  Com- 

pany, Los  Angeles  County 115 

23.  Sewer-pipe  press,  Los  Nietos  plant.  Pacific  Clay  Products  Company 116 

24.  Interior  view  of  plant,  Vitrefrax  Company,  Los  Angeles ^ opp.  122 

25.  California  MuUite  brick  being  fired  in  tunnel  kiln  at  cone  28,  Vitre'rax  Com- 

pany,  Los   Angeles 122 

26.  Clay  and  shale  deposit  of  McNear  Brick  Company,  showing  loading  hopp  r, 

Marin  County 125 

27.  Clark  and  Marsh  Kaolin  Mine 133 

28.  Flint  fireclay  at  portal  of  tunnel.  Goat  Ranch,  Gladding,  McBean  and  Com- 

pany, Orange  County 142 

29.  M  M  2  pit.  Goat  Ranch,  Gladding,  McBean  and  Company,  Orange  County 143 

30.  Plant  of  La  Bolsa  Tile  Company,  Weibling,  Orange  County 143 

31.  Vitrefrax  Company,  entrance  to  upper  chamber  workings,  O'Neill  Ranch  clay 

deposit.  Orange  County 145 

32.  End-cut  during  preparation  of  pit  of  Clay  Corporation  of  California,  Lincoln, 

Placer  County 150 

33.  Clay  pit  of  Gladding,  McBean  and  Company  at  Lincoln,  Placer  County 152 

34.  Airplane  view  of  Gladding,  McBean  and  Company  plant  at  Lincoln 154 

35.  General  view  of  pit  and  plant,  Lincoln  Clay  Products  Company 156 

36    "Eastern  end  of  pit,  Lincoln  Cay  Products  Cnmiiany ■> '"' 

?'«.'  Western  end  of  pit,  Lincoln  Clay  Products  Company 157 

3'S.  Valley  View  Mine,  i>ortal  of  lower  tunnel 160 

39.  Valley  View  Mine,  upper  workings 160 

40.  Southwest  wall  of  main  pit,  Alberhill  Coal  and  Clay  Comn-'ny 164 

41.  Alberhill  Coal  and  Clay  Company,  cut  connecting  main  and  west  pits 165 

42.  Alberhill  Coal  and  Clay  Company,  one  of  the  loading  trestles 165 

43.  Lower  portion  of  west  pit.  Alberhill  Coal  and  Clr>v  Company 166 

44.  Alberhill  Coal  and  Clay  Company,  exposure  of  lignite  coal 167 

45.  Emsco  Clay  Company,  Harrington  pit 170 

46.  Loading  chute,   Emsco   Clay   Company 172 

47.  Gladding,  McBean  and  Company.  Alberhill.  main  tunnel  pit 174 

48.  General  view  of  Alberhill  plant.  Los  Angeles  Brick  Company opp.  176 

49.  Los  Angeles  Brick  Company,  Alberhill  plant,  during  construction 177 

50.  Los  Angeles  Brick  Company,  Alberhill  ])lant,  timnel  driers,  during  construc- 

tion     177 

51.  Los  Angeles  Brick  Company,   Alberhill   plant,   showing  drier  cars  and  brick 

represses    17S 

52.  East  pit,  Los  Angeles  Brick  Company,  Alberhill 179 

53.  Douglas  pit.  Pacific  Clay  Products  Comi)any  at  All>erhill 180 

.')4.   Cannon  and  Company's  plant,  Ben  Ali 184 

55.  Electric  shovel  in  preliminary  cut,  Natoma  Cay  Company 187 

56.  Panama  Pottery  Comiiany's  plant,  near  Sacramento 187 

57.  Fancy  garden  pottery,  manufactured  by  Panama   Pottery  Company 188 

58.  H.  F.  Coors  Kaolin  Deposit.  Hart.  San  Bt^rnardino  County 194 

59.  Pacific  Kaolin  Mine,  Standard  Sanitary  Company,  upper  workings 196 

60.  Pacific  Kaolin  Mine,  Standard  Sanitary  Comnanv.  lower  tnnn-'l  leve' 197 

61.  "Bear   Cat"    shovel    at    Kelly    No.    1    mine.    Pacific    Clay    Products   Company, 

Farr  siding,  San  Diego  County 204 

62.  Wiro  Mine,  fireclay  denosit  east  of  Cardiff,  San  Diego  County 205 

63.  Plant  of  the  Stockton  Fire  Brick  Company.  Stockton 210 

64.  Clay  bins  and  dry  pans  in  plant  of  Stockton  Fire  Brick  Company 211 

65.  Plant  of  San  T^uis  Brick  Works    San  Tjuis  Obisno 214 

66.  M'eiss  clay  deposit,  near  Glen  Ellen.   Sonoma  County 228 

67.  Assay  laboratory,   Stanford   University 242 

68.  Fisk  pre-mi.x  gas-fired  laboratorv  kiln,  in  ceramic  laboratory,  Stanford  Uni- 

versity      243 

69.  Wilson    oxy-acetylene   cone    fusion    furnace    in    ceramic    laborator.v,    Stanford 

University 247 

70.  Cabinet  of  fired  test  pieces,  ceramic  lalioratory,  Stanford  University opp.  257 


LETTER  OF  TRANSMITTAL. 


To  His  Excellencij,  Hon.  C.  C.  Young, 
Governar  of  the  State  of  Calif onvia. 

Sir:  I  have  the  honor  to  herewith  transmit  bulletin  No.  99  of  the 
State  Division  of  Mines  and  Mining  on  the  Clay  Resources  of 
California. 

This  work  deals  in  detail  with  one  of  California's  nonmetallic  mineral 
ijidustries  which  is  annually  growinp'  in  importance  and  value.  Ceramic 
plants  are  being  established  in  increasing  numbers,  existing  plants  are 
lieing  enlarged,  and  a  wide  variety  of  products  is  being  put  on  the 
market.  Our  natural  deposits  of  clays  in  this  state  form  the  basis  upon 
which  these  industries  are  founded. 

This  bulletin  is  the  result  of  over  two  years'  field  and  laboratory 
investigations  conducted  by  Mr.  W.  F.  Dietrich,  associate  professor  of 
mining  engineering  at  Stanford  University;  the  work  being  handled 
on  a  cooperative  basis  between  the  University  and  this  Division. 
Acknowledgement  is  here  maile  of  the  courtesy  aud  cooperatiou  of  Mr. 
Theodore  J.  Hoover,  Dean  of  the  School  of  Engineering  of  Stanford 
University. 

Respect  fully  submitted. 

Lloyd  L.  Root, 

State  iMineralogist. 


CHAPTKK    I. 

IXTRODUCTIOX. 

The  scope  of  this  rei)()rt  is  confined  to  a  study  of  the  raw  materials 
and  manufacturinji'  practice  of  tiiat  part  of  the  ceramic  industry  of 
California  wliich  involves  the  manufacture  of  products  which  "are 
molded  in  the  aqueous  plastic  condition  and  which  derive  their  strength 
from  the  iiartial  fusion  (vitrification)  of  silicates  at  hig'h  temjiera- 
tures.  "^  This  restriction  excludes  ylass,  enameled  metals,  cements,  limes, 
l)lasters,  and  most  abrasives,  whicli  in  modei'n  parlance  are  broadly 
considered  to  belong  to  tlie  field  of  ceramics. 

The  report  inchules  a  brief  technical  description  of  most  of  the  clay- 
working  plants  and  known  clay  deposits  in  California,  together  with  the 
results  of  laboratory  tests  of  the  important  clays  of  the  state..  The 
l)rincipal  emphasis  is  upon  the  economic  and  technologic  phases  of  the 
clay-working  industry  of  California,  rather  tlian  ui)on  its  geologic 
aspects. 

The  field  work  was  done  in  the  summers  of  1925  and  1926,  and  the 
total  time  in  the  field  was  five  months.  In  a  state  luiving  155,652 
s([uai-c  miles  of  land  area,  it  was  obviously  impossible  in  the  period  of 
tile  field  examination  to  make  detailed  investigations  of  all  known  clay 
deposits,  or  to  search  for  new^  deposits  not  already  known  to  the  ceramic 
industry,  the  Mining  Bureau,  or  to  local  inhabitants  in  the  possible  clay 
areas.  Hence  the  principal  value  of  this  report  lies  in  the  fact  that  it 
is  a  record  of  progress  of  the  clay  industry  and  presents  for  the  first 
time  standard  test  data  on  the  known  clays  as  a  basis  of  comparison  for 
new  clays  that  may  be  discovered  in  the  future.  The  uses  of  many  of 
the  clays  that  were  tested  are  very  well  known  from  i^lant  experience, 
so  that  it  should  not  be  difficult  for  the  intelligent  plant  operator  to 
correlate  the  test  data  with  the  results  of  commercial  practice,  not  only 
for  the  clays  now  in  use  in  his  i)lant,  but  for  other  clays  that  have  been 
tested. 

The  search  for  high-grade  clays  on  the  Pacifie  coast  has  received  new 
impetus  in  recent  years  on  account  of  the  phenomenal  increase  in 
])opulation  in  the  region  and  the  consequent  increased  demand  for 
structural  and  decorative  clay  products.  There  seems  little  doubt  that 
this  is  but  the  beginning  of  one  of  the  greatest  ])eriods  of  exjiansion 
that  the  world  has  ever  seen.  If  this  vie-\v  of  the  future  is  correct, 
California  is  destined  to  become  one  of  the  great  ceramic  centers  of 
the  United  States.  That  new  clay  deposits  will  be  discovered  is  almost 
a  foregone  conclusion.  Thus  far,  only  the  obvious  deposits  have  been 
found,  and  only  those  that  can  be  cheaply  mined,  and  that  can  be  used 
without  beneficiation,  have  been  exploited.  The  geologic  column  of 
California  is  practically  complete,  and  there  remain  many  thousands  of 
square  miles  of  land  that  have  never  been  tlioroughly  ])rospected  for 
clays.  Prospectors  and  local  residents  away  from  existing  clay  pro- 
ducing regions  are  on  the  whole  unfamiliar  with  the  nature  of  clays, 
but  it  is  certain  that  their  knowledge  Avill  improve  by  contact  with 
trained  men  who  are  on  the  lookout  for  new  discoveries.  It  is  true  that 
the  abundance  of  cheaply   recoverable  terra  cotta  and  fire  clays  has 

1  Wil.son,   Hewitt,   Ceramics,   p.    2,   McGraw-Hill   Book   Co.,    1927. 


12  DIVISION   OF    MINES   AND   MINING 

heretofore  hindered  the  development  of  iieAV  resources,  but  with  the 
rapid  acquisition  of  the  best  of  these  deposits  by  single  manufacturing 
interests,  and  Avitli  the  increasing  demand  for  new  types  of  clays,  either 
to  displace  those  varieties  now  being  imported  from  outside  of  the  state, 
or  to  make  improved  products,  the  incentive  to  clay  prospecting  will 
be  entirely  adequate. 


METHODS  OF   INVESTIGATION. 

The  field  work  on  the  clay  depositvS  consisted  of  a  visit  to  each  prop- 
erty to  obtain  clay  samples  and  to  prepare  a  description  of  the  develop- 
ment and  mining  operations,  tlie  thickness  of  the  clay  and  overburden 
and  other  features  of  i^ossible  interest.  ]Most  of  the  samples  were  taken 
from  exposed  surfaces,  and  due  precautions  were  taken  to  secure  sam- 
ples that  were  representative  of  the  workable  beds  of  clay.  In  a  few 
places,  samples  were  taken  from  bins  or  storage  piles,  if  these  seemed 
more  suitable  for  securing  representative  samples  than  the  clay  banks. 
In  some  instances,  samples  were  submitted  by  the  clay  producers  them- 
selves as  being  representative  of  their  deposits.  A  number  of  core 
drill  samples  were  obtained  from  the  lone  district,  through  the  courtesy 
of  S.  E.  Kieffer. 

The  plant  descriptions  were  nearly  all  prepared  by  the  author  after 
an  inspection  of  the  plant.  Many  of  these  descriptions  were  submitted 
to  the  plant  executive  for  approval  before  publication.  A  few  descrip- 
tions were  prepared  by  members  of  the  organization  concerned. 

Descriptions  of  a  number  of  plants  that  were  started  subsequent  to 
the  field  investigation  or  that  were  overlooked  by  the  author,  Avere  pre- 
pared by  ^Messrs.  Laizure,  Logan,  or  Tucker,  district  engineers,  Division 
of  ]Mines  and  ^Mining. 

The  test  Avork  Avas  done  in  the  ceramic  laboratory  of  the  Department 
of  ^Mining  and  ^Metallurgy  at  Stanford  University  by  methods  described 
in  Chapter  IV. 

PREVIOUS  WORK. 

The  clays  and  clay  industries  of  California  AA-ere  described  in  two 
earlier  reports^  of  this  Bureau.  These  reports  include  descriptions  of 
knoAvn  deposits  and  of  the  operating  plants,  but  contain  very  fcAV  data 
on  the  ceramic  properties  of  the  clays. 

Most  of  the  county  reports  of  the  Bureau  contain  descriptions  of  clay 
deposits  and  clay-Avorking  plants  that  Avere  prepared  by  members  of 
tlie  State  Mineralogist's  staff.  In  a  number  of  cases  these  descriptions 
are  sufficiently  up  to  date  to  permit  their  use  in  the  present  report, 
and  are  reprinted  here  for  the  sake  of  completeness  and  continuity,  as 
the  county  reports  are  scattered  through  a  number  of  volumes  of  the 
State  Mineralogist's  reports. 

An  important  article-  on  the  Alberhill  clays  by  the  late  J.  H.  Hill, 
then  president  of  the  Alberhill  Coal  and  Clay  Company,  Avas  pub- 
lished bA'  tlu'  Bui'eau  in  192:^. 


'  Stiiutural  ami  Industrial  Materials  of  California:  Cal.  State  Min.  Bur.,  Bulletin 
3S,  part  111,  pp.   i;tu-25y,   190G. 

The  Clav  Industry  in  California:  Cal."  State  Min.  Bur.,  Prel.  Report  No.  (,  102 
pages,    ly20. 

=  Hill,  J.  H.,  Clav  deposits  of  the  Alberhill  Coal  and  Clay  Company:  State  Miner- 
alogist's Report  XiX,  pp.   185-210,   1923. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  13 

The  foraiuif  |)r()i)oitios  mid  cliemieal  analyses  of  certain  clays  from 
tlie  Alberliill  district  liave  bi-en  jjfiviMi  by  I>nrclifi('l.' 

Tlio  clay  iiiininir  and  jjropai'atioii  plant  of  tlic  Clay  Corporation  of 
California,  at  Lincoln,  has  been  described  by  C.  N.  Schuette.- 

AU  of  the  foregoing  references  were  freely  used  in  the  preparation 
of  this  bulletin,  even  at  the  cost  of  repetition,  as  it  was  desired  to  bring 
together  in  one  vohnne  all  of  the  avaihd)lc  infoi'iiiation  on  the  ('la\' 
resources  of  the  state. 

ACKNOWLEDGMENTS. 

In  a  work  of  this  nature  it  is  impossible  to  give  individual  acknowl- 
edgment to  all  those  who  contributed  to  it.  The  writer  wishes  to 
express  his  apjn-eciation  of  the  courtesies  that  were  extended  to  him  by 
many  i)crsons  connected  with  the  ceramic  industry  of  California. 
Their  cooperation  in  making  this  bulletin  possible  is  especially  note- 
worthy in  view  of  the  fact  that,  on  the  whole,  the  ceramic  industry 
today  remains  as  one  of  the  few  mineral  industries  that  extensively  uses 
secret  processes  and  secret  formulae. 

Prof.  He\\'itt  Wilson  of  the  University  of  Washington  rendered 
invaluable  assistance  in  outlining  the  methods  of  clay  testing  aiul  in 
making  many  valuable  suggestions  and  criticisms. 

Mr.  John  T.  Roberts,  president  of  the  Stockton  Fire  Brick  Company, 
generously  contributed  equipment  and  refractories  to  the  ceramic 
laboratory  in  which  the  test  work  was  done,  and  was  ever  ready  to  give 
valuable  advice  and  infoi-mation  during  the  progress  of  the  work. 

^Ir.  L.  M.  Richard,  consvilting  economic  geologist  for  Gladding, 
McBean  and  Company,  was  especially  heli)ful  in  the  field  in  the 
Alberhill-Corona  district,  and  contributed  many  ideas  concerning  the 
organization  of  the  report. 

Several  graduate  students  in  metallurgy  or  ceramics  at  Stanford 
University  contributed  to  various  phases  of  the  investigation,  especially 
in  the  laboratory.  Among  these  should  be  mentioned  V.  J.  ^linner, 
C.  W.  Brigg.s,  H.  J.  0 'Carroll,  D.  R.  Irving  and  R.  E.  Paine. 

Acknowledgment  is  also  due  to  Messrs.  Walter  W.  Bradley,  W.  Bur- 
ling Tucker  and  C.  A.  Logan  of  the  Division  of  ]\Iines  and  Mining  for 
assistance  in  compiling  data,  and  for  many  helpful  suggestions  regard- 
ing the  conduct  of  the  work.  In  addition,  Messrs.  Tucker,  Logan,  and 
C.  ]\IcK.  Laizure  supplied  a  number  of  descriptions  of  deposits  or  plants 
not  visited  by  the  author,  acknowledgments  of  which  are  made  in  the 
text. 

GENERAL    REFERENCES. 

Little  space  has  been  devoted  in  this  report  to  the  origin  of  clay,  its 
chemical  and  physical  properties,  or  to  clay-working  processes  in  gen- 
eral. Such  information  has  usually  been  included  in  clay  reports  from 
other  states,  but  there  seems  little  justification  for  its  inclusion  here, 
in  view  of  the  fact  that  there  are  now  a  number  of  excellent  texts  for 
those  who  desire  such  information.  A  few  of  the  more  important 
works  are  listed  below : 


•  Burchfiel,    B.    M..  Refractory    clavs    of    the    Alberhill,    California,    deposits:    Jour. 

Amer.  Cer.   Soc,  Vol.  6.  pp.   1167-1175,   1923. 

=  Schuette,    C.    N.,  Engineering    principles    applied    to    the    exploitation    of    a    clay 

deposit:  Eng.  &  Min.  Jour.-Press,  Vol.  121,  p.   964,  June  12,   1926. 


14  DIVISION   OP    MINES   AND   MINING 

Wilson,  Hewitt,  "Ceramics."  McGraw-Hill  Book  Co.,  New  York, 
1927.  An  excellent  text  on  clay  technology,  coA^ering  the  chemical  and 
physical  properties  of  clays.  Not  suitable  for  readers  who  have  no 
knowledge  of  chemistry  or  physics. 

Andrews,  A.  I.,  "Ceramic  Tests  and  Calculations."  John  Wiley 
and  Sons,  1928.  An  elementary  text  on  the  methods  of  clay  testing, 
and  on  the  calculations  relative  to  glazes,  bodies,  enamels  and  glasses. 

xSearle,  A.  B.,  "The  Chemistry  and  Physics  of  Clays  and  Other 
Ceramic  Materials."  Ernest  Benn,  Ltd.,  London,  1924.  A  valuable 
reference  work  of  scientific  conceptions  and  data  on  clays.  Particularly 
useful  to  research  workers. 

Ries,  Ileinrich.  "Clays,  Their  Occurrence,  Properties  and  Uses,"  3d 
Edition.  John  Wiley  and  Sons,  1927.  The  standard  work  on  the 
geology  and  origin  of  clays,  with  sufficient  information  on  properties 
and  uses  to  serve  as  an  elementary  text.  Perhaps  the  best  general 
work  for  tlie  layman. 

"Clay  Products  Cyclopedia  and  Equipment  Catalog."  Issued  annu- 
ally by  Industrial  Publications,  Inc.,  Chicago,  Illinois.  A  useful 
reference,  of  particular  value  as  a  dictionary  of  ceramic  nomenclature 
and  for  the  descriptions  and  illustrations  of  ceramic  equipment. 


to 


CLAY  KESOUUeES  AXD  fEKA.M  U'   IXDUSTUV  15 


Chapter  IT. 
SUMMARY  OF  THE  CERAMIC  INDUSTRY  OF  CALIFORNIA. 

INTRODUCTION. 

For  the  benefit  of  those  who  may  be  unianiiliar  witli  ehiy-working 
processes,  a  brief  summary  of  clay  technology  is  given. 

Definiticyn  of  clay:  "Clays  are  the  weathered  products  of  tiic  silicate 
rocks,  containing  sufficient  hydi-ous  silicate  of  alumina  in  the  softened 
condition  to  ])roduce  a  ])]astic  or  semiplastic  nuiss  when  tempered  Avith 
water.  "^  Clays  may  be  classified  into  many  types.  In  this  report  a 
classification  is  used  that  is  based  upon  physical  properties  and  uses. 
The  details  of  this  classification  are  given  in  Chapter  IV. 

Definitions  of  a  few  of  the  more  general  terms  used  in  clay  momencla- 
ture  are  given  below  :- 

Kaolin  is  amorphous  hydrated  aluminum  silicate,  corresponding  to 
the  formula  of  Al20..5.2Si6^.2HoO  and  is  the  most  important  constituent 
of  china  clay.  The  term  is  \ndely  used  in  commercial  practice  to 
include  china  clay  and  rock  higli  in  china  clay. 

China  clay  is  the  commercial  variety  of  kaolin.  It  may  occur 
naturally  in  deposits  of  sufficient  purity,  but  is  more  often  prepared  by 
the  purification  of  natural  deposits.  It  burns  white,  and  has  high 
refractoriness,  but  the  plasticity  is  generally  poor. 

Ball  clays  are  white  or  light-cream-burning  clays  of  high  plasticity 
and  bonding  power  that  vitrify  to  dense  impervious  bodies  at  compara- 
tively low  temperatures. 

Fireclays  are  those  clays  that  withstand  high  temperatures,  par- 
ticularly those  that  do  not  fuse  at  temperatures  below  1605°  C. 
(2921°  F.,  cone  27).  They  are  used  in  the  manufacture  of  fire  brick 
or  other  refractories  and  are  often  used  for  architectural  terra  cotta, 
wall  tile,  etc. 

Face  brick  clays  maj-  be  divided  into  one  of  three  groups.  (1) 
Red-burning  clay;  (2)  white-burning  clay;  (3)  buff -burning  clay. 
The  color,  ])lasticity,  shrinkage,  and  vitrification  must  fall  within  cer- 
tain general  limits,  dependent  upon  the  type  of  brick  to  be  manufac- 
tured. 

Common  brick  clays  vary  widely  in  their  composition  and  proji- 
erties.  TJiey  are  usually  high  in  fiuxes  and  in  most  cases  are  I'ed-burn- 
ing.  They  should  mold  easily  and  develop  hardness  and  strength  at  as 
low  a  firing  temperature  as  possible  without  seriously  warping  or 
cracking. 

Slip  clays  are  fine  grained,  and  contain  a  high  proportion  of  fluxes. 
They  should  melt  at  a  low  temperature  (preferablj^  below  1200°  C, 
cone  5)  to  a  greenish  or  brown  glass  to  form  a  natural  glaze. 

CJaij  preparation:  With  the  exception  of  some  of  the  lieavj^  struc- 
tural products,  it  is  seldom  possible  to  find  a  single  raw  material  that 

•  Wilson.  Hewitt,   Ceramics.  ]).   7. 

=  See  Wilson,  op.  cit..  pp.  28-39,  and  Clay  Products  Cyclopedia,  1926,  pp.  94-96,  for 
further  details.      "  ' 


16  DIVISION  OF   MINES  AND  MINING 

possesses  the  desired  plastic,  tli yi(i<i'  and  lirin<>'  cliaractcri.stics  tor  mak- 
ing a  given  ceramic  product.  It  is  usually  necessary,  therefore,  to 
blend  several  clays  and  nonplastics  in  order  to  control  the  properties 
of  the  finished  ])roduct.  For  example,  clays  having  different  per- 
centages of  iron  may  be  blended  to  secure  the  desired  color ;  highly 
]dastic  clays  may  be  blended  with  those  having  poor  plasticity  in  order 
to  control  shrinkage  and  porosity ;  feldspar  may  be  added  as  a  flux  to 
lower  the  temperature  of  vitrification;  crushed  qiuirtz  or  crushed  cal- 
cined clay  may  be  used  as  a  "grog"  to  produce  a  skeleton  structure 
that  is  bonded  by  the  clay,  giving  greater  strength  and  less  tendency 
to  warp  than  if  clay  alone  were  used. 

After  deciding  upon  the  proportions  of  the  various  raw  materials, 
some  of  them  are  ground  separately  and  others  are  ground  after  mixing, 
either  by  dry  or  wet  methods.  Ball  mills  and  grinding  pans  are  the 
principal  types  of  machinery  used  for  fine  grinding.  At  some  point 
in  the  process,  all  the  materials  are  mixed  together,  the  proper  amount 
of  water  is  added,  and  the  mass  is  subjected  to  a  thorough  mixing,  with 
or  without  additional  grinding.  For  the  manufacture  of  many  types 
of  ware,  the  plastic  mass  is  allowed  to  age  in  humidified  rooms  or  under 
wet  sacking  for  a  period  of  24  hours  to  one  month,  in  order  to  secure 
uniform  distribution  of  the  water  and  to  develop  maximum  plasticity. 

Manufacturing  processes:  After  the  clay  is  properly  prepared,  the 
three  essential  steps  in  the  manufacture  of  a  ceramic  product  of  the 
type  under  consideration  are  shaping,  drying  and  firing.  A  fourth 
l)rocess  that  is  applied  to  certain  types  of  ware  is  glazing. 

Shaping":  The  shaping  of  clay  wares  may  be  done  while  the  clay  is 
in  one  of  the  four  different  degrees  of  plasticity:  (1)  Drj^  pressing  of 
pulverized  mixtures  to  which  has  been  added  just  enough  water  to  bind 
the  mass  together  when  subjected  to  pressure  in  hydraulic,  cam.  or 
screw  presses.  This  process  is  principally  used  for  shaping  floor  and 
wall  tile,  especially  the  hard  vitrified  tile  used  in  bath-room  floors,  and 
to  some  extent  it  is  used  in  common  brick  and  face  brick  manufacture. 
(2)  Stiflf-mud  shaping,  in  which  si\fBcient  water  is  added  to  tlie  clay  to 
permit  the  mass  to  floAv  through  a  die  without  rupture.  A  column  of 
clay  is  pushed  through  a  hollow  die  by  a  plunger  or  screw  or  the  clay 
may  be  jiressed  into  a  steel  mold  by  a  plunger.  This  is  the  usual 
process  for  making  common  brick,  face  brick,  fire  brick,  and  roofing 
tile,  and  is  the  only  method  in  use  for  shaping  hollow  tile,  sewer  pipe, 
drain  tile,  and  electrical  conduit.  (3)  Soft-mud  shaping,  in  which 
almost  enough  water  is  added  to  cause  stickiness.  This  consistency  is 
used  for  the  hand  pressing  of  terra  cotta  and  tile  in  plaster  molds,  for 
the  shaping  of  pottery  and  stoneware  on  pottery  wheels  or  in  molds, 
for  the  hand  molding  of  roofing  tile  over  paper  covered  wooden  molds, 
or  for  the  hand  or  mechanical  pressing  of  common  brick  or  face  brick. 
(4)  Casting,  in  which  the  finely-ground  mixture  is  suspended  in  water 
so  that  the  resultant  "slip"  may  be  poured  into  plaster  molds.  The 
plaster  absorbs  water  from  the  slip,  gradually  precipitating  the  solids 
asainst  the  inner  walls  of  the  mold.  When  the  Avails  are  thick  enough, 
the  surplus  slip  is  poured  from  the  mold,  the  object  is  left  in  the  mold 
until  stiff  enough  to  stand  its  own  weight,  then  the  mold  is  stripped 
off  and  the  shape  allowed  to  dry.     Casting  is  the  cheapest  method  of 


(LAV  KES0UKCE8  AND  C'EKA.MU    INDL'STKV  17 

producing  pottery  on  a  large  scale,  and  is  the  principal  method  in  use 
for  shaping  sanitary  porcelain. 

Drying:  The  drying  of  clay  wares  may  be  done  under  sheds  in 
the  open,  in  specially  heated  rooms,  or  in  specially  designed  humidity 
dryers  in  which  the  three  factors  of  time,  temperature  and  humidity  are 
under  close  control.  The  type  of  drying  will  depend  upon  the  charac- 
teristics of  the  clay  used  and  u])on  the  sliape  and  size  of  tlie  ware  to  be 
dried.  As  clay  shrinks  dvirinu  drying,  it  is  important  that  the  drying 
be  controlled  in  such  a  way  as  to  avoid  undue  strains  which  might 
cause  cracks  in  the  dried  ware,  or  lines  of  weakness  which  would  i-esult 
in  cracks  during  the  subsequent  firing  operation. 

Firing:  The  i)roper  firing  of  ceramic  ware  is  perhaps  the  most 
important  part  of  the  process,  and  many  tyi)es  of  kilns  are  available 
for  the  purpose.  The  essential  conditions  to  be  met  by  a  ceramic  kiln 
are  control  of  the  time-temperature  cj^cle  and  unifoi-mity  of  heat  dis- 
tribution. In  some  cases,  kiln  gases  can  not  be  allowed  to  come  in 
contact  with  the  ware,  so  that  mufiie  kilns  are  necessary,  or  else  the  ware 
is  enclosed  in  fireclay  receptacles  known  as  "saggers."  Most  kilns 
now  in  use  are  of  the  periodic  type,  but  there  is  a  growing  tendency  to 
use  continuous  kilns  in  which  the  ware  is  set  on  trucks  which  move 
through  a  tunnel  that  is  fired  near  its  mid-point.  Firing  temperatures 
range  from  895°  C.  (1643°  P.)  for  soft-burned  common  brick  to 
1350°  C.  (2462°  F.)  for  hard  porcelain  and  fire  brick.  A  few  special 
products  are  fired  as  high  as  1640°  C.  (2984°  F.).^ 

Glazing:  Glazing  may  be  done  by  dipping,  spraying,  or  painting  a 
water  suspension  of  the  glaze  ingredients  on  the  ware  either  before 
firing,  or  after  a  preliminary  (biscuit)  firing.  In  some  cases  where 
complicated  polychrome  decorations  are  used,  several  firings  are 
necessary  before  the  piece  is  finished.  Salt  glazing  is  another  method, 
wherein  common  salt  is  vaporized  in  the  kiln  during  firing,  the 
sodium  of  the  salt  reacting  with  the  clay  body  to  form  a  fusible  com- 
pound. 

CLAY   DEPOSITS  OF  CALIFORNIA. 

hi  practically  all  of  the  low  altitude  areas  of  California  there  is  an 
abundance  of  common  clay  and  shale  suitable  for  the  manufacture  of 
common  brick  and  hollow  building  tile.  By  reason  of  the  low  unit 
value  of  these  ])roduets,  the  raw  material  must  be  chea]")ly  mined,  and 
will  not  stand  transportation  charges  from  points  very  distant  from 
the  brick  yards,  which  are  situated  near  the  centers  of  consumption. 
In  the  San  eloaquin  and  Sacramento  valleys,  it  has  been  difficult  to 
find  good  bodies  of  clay  with  sufficient  plasticity  for  the  manufacture 
of  the  best  quality  of  building  brick,  and  some  of  the  plants  in  this 
area  have  been  forced  to  ship  plastic  clay  from  dift'erent  points  to 
mix  with  the  local  materials.  In  the  San  Francisco  Bay  district  and 
in  Los  Angeles  County,  the  two  important  centers  of  consumption, 
there  are  ample  common  clay  resources.  The  same  is  true  of  the 
smaller  valleys  in  the  Coast  Range  and  in  the  foothills  of  the  Sierra 
Nevada. 

In  the  mountainous  portions  of  the  state,  in  the  desert  regions,  and 
in  the  volcanic  area  of  the  northeastern  counties,  it  is  difficult  to  find 


1  Pyrometric  cones  are   extensively  used   in   the   ceramic   industry   as   temperature 
indicators.     See  table  No.  9  in  Chapter  IV. 
2 — 54979 


18  DIVISION   OF    MINES   AND   MINING 

suitable  coinniou  brick  clays,  but  as  these  areas  will  probably  never  be 
thickly  populated,  such  brick  as  are  needed  can  be  shipped  in  from 
more  distant  points. 

Tlie  demand  for  paving  brick  lias  never  been  great  enough  to  k'ad 
to  an  intensive  search  for  red-burning  shales  of  the  type  used  elsewhere 
in  the  United  States  for  paving  brick  manufacture.  A  few  such  shales 
are  known,  and  one  or  two  deposits  are  being  worked,  but,  for  the  most 
part,  the  demand  for  paving  brick,  sewer  pipe,  conduit  pipe,  and  other 
red-burned  vitrified  products  has  been  met  by  a  blending  of  various 
clays,  with  or  without  grog.  Three  deposits  are  of  special  interest  in 
this  connection:  the  Natoma  da}'  (see  samples  No.  210  and  212), 
which  consists  of  fine  gold-dredge  tailings  deposited  in  settling  basins ; 
the  Goat  Ranch  shale  (see  sample  No.  282),  an  Upper  Cretaceous  shale 
in  Santa  Ana  Canyon;  and  the  Santa  ]\Iargarita  shale  (see  samples 
No.  216  and  217),  from  an  undeveloped  deposit  along  the  Southern 
Pacific  Railroad  near  Santa  IMargarita. 

The  general  distribution  of  the  high-grade  clays  of  California  is 
shoAvn  on  Plate  I. 

The  high-grade  clays  of  the  state  are  found  mainly  in  deposits  of 
Eocene  age,  although  there  is  one  important  area  of  Pleistocene  clay, 
and  the  importance  of  certain  beds  in  the  Upper  Chico  (Cretaceous)  is 
just  receiving  recognition.  Approximately  90  i)er  cent  of  the  high- 
grade  clays  of  the  state  are  now  being  mined  from  one  of  three  areas: 
the  Alberhill-Corona  district  in  Riverside  County ;  the  lone  district  in 
Amador  County ;  and  the  Lincoln  district  in  Placer  County.  The  age 
of  the  clays  in  all  three  districts  is  Eocene,  and  the  dei>osits  were 
formed  by  sedimentation  in  inland  seas,  with  or  Avithout  subsecpient 
alteration. 

The  Alberhill-Corona  clays  occur  in  an  area  in  the  Temescal  Valle}' 
some  twelve  miles  long  and  two  miles  wide.  In  many  places  the  clay 
beds  are  three  to  four  hundred  feet  thick.  The  clays  were  laid  down  in 
Eocene  time  in  an  arm  of  the  sea.  The  region  is  characterized  by  a 
discontinuity  of  structure  that  arose  from  folding,  faulting,  and  erosion 
subsequent  to  clay  deposition,  and  by  extreme  local  variations  in  the 
individual  clay  beds  caused  by  variations  in  the  conditions  of  sedi- 
mentation. A  wide  variety  of  red,  pink,  and  buff-burning  i)lastic  clays 
and  a  good  range  of  plastic  and  semi-plastic  fireclays  are  produced  in 
the  district.  The  colored  clays  are  used  for  face  brick,  roofiug  tile  and 
red  earthenware,  and  as  an  ingredient  of  sewer  pipe,  electrical  conduit 
and  other  mixes.  The  buff-burning  clays,  generally  refractory,  are 
used  for  architectural  terra  cotta,  stoneware,  decorative  tile,  pottery, 
etc.  The  refractory  clays  are  used  for  fire  brick  and  other  refractory 
shapes.  A  few  selected  varieties  are  sufficiently  free  from  coloring 
compounds  to  ])ermit  their  restricted  use  in  white-burned  products. 
The  typical  clays  are  chai-acterized  by  excellent  plasticity,  low  or 
medium  dry  strength,  low  or  medium  drying  and  firing  slirinkage,  and 
open  fired  texture.  A  few  varieties  are  found  that  possess  high  dry 
strength  and  high  shrinkage,  and  that  vitrify  completely  within  com- 
mercial firing  ranges,  but  these  are  the  exception  rather  than  the  rule. 
The  proportion  of  sand  in  the  clays  varies  widely  from  almost  pure 
sand  to  pure  clay,  resulting  in  a  wide  range  of  commercial  varieties. 

The  lone  clays  and  sands  occur  in  a  belt  about  twelve  miles  long  and 
one-half  to  one  mile  wide.     The  total  thickness  of  clay  is  not  knoA\Ti, 


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SHOWING 
LOCATIONS   OF  HIGH-GRADE 

CLAY  DEPOSITS 

FROM  WHICH  SAMPLES  WERE  TAKEN. 

JANUARY.  1928. 

ACCOMPANYING   BULLETIN  No. 99. 


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CLAY  RESOURf'ES  AXD  fERA:Mrr  INDUSTRY  19 

but  in  a  nuinber  of  places  a  tliiekness  of  over  100  feet  lias  been  demon- 
strated. The  beds  are  more  continuous,  and  have  less  local  variations 
in  the  character  of  the  material,  tlum  is  the  case  at  Alberhill.  The 
area  is  important  for  its  liiyh-yrade  (iiechiy  and  tire-saiui.  Some  plastic 
pink-  and  buft'-burnin<>:  clays  are  also  produced  for  use  in  terra  cotta, 
stoneware  and  pottery  manufacture.  The  fireclays  are  the  most 
refractory  that  have  thus  far  been  found  in  the  state,  but  are  charac- 
terized by  low  dry  strengtii  and  high  firing  shrinkage,  with  a  strong 
tendency  to  crack  when  fired.  The  fire-sands  are  composed  of  quartz- 
mica  saiul  with  from  10  to  25  ])er  cent  of  clay,  and  are  im])ortant  as  a 
nonplastic  ingredient  of  fire  brick  mixtures,  to  diminish  the  shrinkage 
and  the  tendency  to  crack.  Future  develoi)ments  in  tliis  area  are 
expected  to  greatl.y  extend  the  known  dimensions  of  the  clay  beds,  and 
to  disclose  other  varieties  of  clay  not  now  accessible. 

The  Lincoln  clays  lie  in  an  isolated  remnant  of  the  lone  formation 
(Eocene),  protected  by  a  lava  capping.  The  beds  underlie  a  low  hill 
adjoining  the  toAvn  of  Lincoln.  The  claj^  is  continuous  over  an  area  of 
about  four  square  miles,  to  a  depth  of  ap])roximately  100  feet  below 
the  lava  capping.  The  Lincoln  clay  is  an  excellent  butf-burning  plastic 
fireclay  that  is  especially  valuable  in  the  manufacture  of  architectural 
terra  cotta,  faience  tile,  fire  brick,  and  other  products.  There  are  also 
beds  of  pink-burning  clays  that  are  used  in  seAver  pipe,  roofing  tile  and 
face  brick  mixtures.  The  Lincoln  clays  have  excellent  plasticity, 
medium  dr}-  and  fired  strength,  a  long  vitrification  range,  and,  although 
the  shrinkage  is  high,  the  clay  can  stand  rapid  firing  without  cracking. 

Some  other  clay  producing  areas  of  lesser  importance  are:  (1)  The 
Cardiff-Carlsbad  area  in  San  Diego  County,  containing  excellent 
fireclays,  some  of  whicli  are  closely  similar  to  the  famous  (Iros-Almerode 
fireclays  of  Germany;  (2)  The  Santa  Margarita  Rancho  deposit,  near 
San  Juan  Capistrano,  San  Diego  County,  containing  important  deposits 
of  higldy  aluminous  fireclay;  (8)  The  Hunter  Ranch  deposit,  near  El 
Toro,  Orange  County,  where  there  is  an  excellent  firecla.y,  associated 
with  a  bed  of  kaolin  and  sand  from  which  a  high-grade  kaolin  can  be 
recovered;  (4)  The  Goat  Rancli  deposit,  in  Santa  Ana  Canyon,  Orange 
County,  an  TTpper  Chico  (Cretaceous)  deposit  of  flint  fireclay. 

California  is  especially  favored  with  resources  of  noni)lastic  ceramic 
materials.  At  Campo,  San  Diego  County,  is  a  large  de])osit  of  excel- 
lent felds]iar.  and  many  other  feldspar  deposits  are  known  in  southern 
California.  Silica  is  available  in  many  forms  in  California  and  near 
the  border  in  Nevada.  A  large  deposit  of  quartzite  has  been  found  in 
the  desert  south  of  Barstow,  from  which  silica  brick  is  being  made. 
Talc,  used  in  some  floor-tile  bodies,  is  available  from  a  number  of 
sources.  The  most  extensive  deposits  of  andalusite  and  cyanite  in  the 
United  States  occur  in  California.  These  minerals  are  of  increasing 
importance  in  the  manufacture  of  high-grade  refractories. 

The  most  im])ortant  ceramic  materials  that  are  thus  far  lacking  in 
California  are  ball  and  chitia  clays  equal  in  purity  and  iniiformity  to 
those  from  the  deposits  of  England  or  from  the  eastern  T'^'nited  States. 
A  clay  possessing  the  projierties  of  a  mixture  of  the  two  varieties  has 
been  found  in  San  Bei-nai-dino  County,  and  a  good  china  clay  has  been 
found  in  Nevada,  but  thus  far  ])roduction  has  been  small,  and  most  of 
the  ball  and  china  clay  requirements  of  the  California  industry  are  met 
by  importation  from  the  eastern  states  or  from   England.     One  of 


20  DIVIRIOX   OF    MIXES   AND   MINING 

the  factors  that  lias  liindered  the  establishment  of  a  local  clay  Avash- 
ing  industry  to  produce  china  clay  is  the  low  price  of  Beljiian  "lass 
sand  at  Pacific  coast  ports,  making:  it  unprofitabh^  to  market  tlie  (piartz 
sand  which  would  be  a  by-product  of  kaolin  waslnng-.  Since  the  yield 
of  kaolin  would  be  but  20  to  30  pec  cent  from  the  known  deposits  in 
California,  the  importance  of  a  satisfactory  market  for  the  sand  is 
apparent. 

Wliile  a  few  small  deposits  of  bone  clay  have  been  found  in  southern 
California,  highly  aluminous  clay  is  relatively  scarce,  and  no  commer- 
cial deposits  of  diaspore,  bauxite  or  gibbsite^  have  been  discovered  in 
California. 

MINING    METHODS. 

Most  of  the  clay  deposits  of  California  are  mined  by  open  pit 
methods,  and  with  the  exception  of  most  of  the  common  clay  deposits, 
hand  methods  predominate.  Where  a  production  of  the  order  of  one 
car  (50  tons)  per  day  or  more  is  needed  mechanical  methods  are  in 
general  use,  if  topographic  features  are  favorable,  and  if  no  hand  sort- 
ing of  the  clay  is  necessary. 

Drilling  and  blasting  are  necessary  at  many  of  the  deposits.  The 
holes  are  usually  drilled  with  hand  augers,  and  blasted  with  light 
charges  of  low-power  explosives.  As  a  rule  3  nearly  vertical  bank  is 
carried,  and  the  height  of  the  bank  corresponds  to  the  thickness  of  the 
bed  being  mined.  Stripping  of  overburden,  if  any,  is  carried  out  in 
advance  of  mining,  on  a  separate  bench. 

The  hand  methods  in  use  involve  pick  and  shovel  loading  into  auto 
trucks,  wagons,  mine  cars,  wheelbarroAvs,  or  loading  chutes,  depending 
on  local  conditions. 

The  mechanical  methods  include  horse-drawn  scrapers.  ]iower-driven 
drag  scrapers,  and  power  shovels  of  various  types  actuated  by  gasoline 
or  electricity.  The  scrapers  usually  load  directly  into  hoppers,  from 
Avhich  the  clay  is  drawn  oif  into  auto  trucks,  industrial  railway  cars, 
or  onto  belt  or  bucket  conveyors.  The  shovels  load  into  auto  trucks,  or 
into  industrial  or  standard  railway  cars. 

Most  of  the  underground  mining  is  done  by  the  room  aiul  pillar 
method,  from  a  tunnel  entry,  with  only  such  auxiliary  timber  support 
as  is  necessary  to  support  localized  blocks  of  loose  ground.  While 
pillars  are  robbed  as  much  as  is  practicable,  from  20  to  35  i)er  cent  of 
the  clay  must  be  left  in  the  pillars  to  support  the  workings. 

Transportation  from  the  pit  to  the  plant  or  railroad  siding  is  done  at 
many  properties  in  the  original  vehicle  in  which  the  clay  is  loaded.  At 
other  properties  a  loading  platform  or  chute  is  placed  as  near  the  pit 
as  possible,  and  the  clay  is  transferred  to  cars  on  an  industrial  railroad 
or  into  auto  trucks. 

Most  of  the  clay  mining  in  the  state  is  done  on  contract,  especially 
at  smaller  properties.  To  one  familiar  Mith  metal  mining,  the  methods 
in  use  at  many  of  the  properties  seem  needlessly  crude  and  wasteful  of 
human  energy,  but  the  short  working  season,  seldom  longer  than  from 

1  These  three  minerals  are  t\'pes  of  aluminum  hydi  -)xide.  Diaspore  contains  12-14 
per  cent  of  water  and  has  a  formula  approximating  to  AloO^i.HoO.  Bauxite  contams 
20-24  per  cent  of  water  and  corresponds  to  AI0O3.2H.O.  Gibbsite  contams  27-3o 
per  cent  of  water  and  corresponds  to  AloO.-..3HoO.  See  Searle  "The  Chemistry  and 
Phvsics  of  Clavs,"  p.  3.39.  The  bauxites  are  used  in  the  manufacture  of  metallic 
aluminum,  and'  are  valuable  for  the  manufacture  of  a  .superior  type  of  fire  brick 
(diaspore  brick)  that  is  more  refractory  than  ordinary  fireclay  brick.  These 
brick  are  used,  among  other  purposes,  for  lining  the  clinkpring  zone  of  cement  kilns. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  21 

'Siny  to  October,  the  eoinparatively  small  seale  of  operation,  the  fluctua- 
tion of  demand,  the  irre«iularity  and  small  size  of  some  of  the  deposits, 
the  necessity  of  hand  sortin.n'  in  a  number  of  cases,  and  the  fact  that 
many  of  the  deposits  are  mined  uiuler  a  royalty  lease,  all  must  be  <riven 
due  consideration  before  any  valid  criticisms  can  be  made. 

Clay  minintr  costs  for  oj^en  i>it  work  range  from  10^  to  25^'  })er  ton 
for  scraper  or  shovel  loading,  to  2()(^  to  aO^  ])er  ton  for  hand  loading. 
Hand  sorting  nuiy  double  the  cost  of  liaiul  loading.  Transportation  to 
the  pit  mouth,  or  to  a  bin  within  a  few  hundi'ed  yards  of  the  pit,  may 
add  fi-om  o^  to  2o^'-  ])er  ton.  liieidentals  may  total  from  'h-  to  25^, 
making  the  total  direct  cost  vary  between  the  approximate  limits  of  20^ 
and  $1.50  per  ton.  In  addition,  many  of  the  properties  are  several 
miles  from  a  railroad  or  plant  and  must  stand  a  transjiortation  cost 
that  may  be  in  excess  of  $1  per  ton.  The  longest  auto  truck  haul  noted 
was  15  miles,  aiul  there  are  a  number  of  deposits  where  the  haul  is  from 
thi-ee  to  eight  miles  from  the  pit  to  a  railroad  or  plant.  Where  a 
royalty  is  paid,  the  charge  is  usually  from  lO^'-  to  25^  per  ton. 

rnderground  mining-  costs  are  naturally  higher  than  open  pit  costs, 
but  the  direct  cost  of  mining  and  loading,  including  hand  sorting,  is 
seldom  in  excess  of  .$1  per  ton.  Haulage  and  t ranspoi'tation  costs  must 
be  added. 

As  an  indirect  indication  of  costs,  the  selling  prices  of  a  number  of 
clays  may  be  cited :  The  price  of  Alberhill  clay  f.o.b.  gondola  cars  at 
Alberhill  ranges  from  $1  per  ton  for  the  cheaper  grades  that  occur  in 
large  deposits  and  that  are  chea))ly  mined  by  mechanical  methods,  to 
$5.50  per  ton  for  the  rarer  varieties  that  are  hand  sorted  and  may  be 
mined  by  uiulerground  methods.  The  price  of  Lincoln  clay,  mined  by 
a  ])ower  shovel  from  a  large  ])it.  is  nominally  $1.75  ]ier  ton,  f.o.b. 
Liiu;oln. 

CERAMIC   PLANTS. 

A  check  list  of  tiie  clay-working  jilants  of  (•alifornia,  with  the 
products  made  in  each,  is  given  in  Table  1.  It  will  be  noted  that  the 
majority  of  the  plants  in  the  state  are  in  or  near  the  two  major  centers 
of  po])ulation  and  industry,  the  Los  Angeles  area,  and  the  San  Fran- 
cisco Bay  district.  However,  common  brick  and  hollow-tile  plants  are 
well  distributed  among  the  lesser  centers  of  population,  and  there  are  a 
number  of  important  manufacturers  of  high-grade  ceramic  products 
whose  ]>lants  are  at  some  distance  from  the  larger  centers.  Some  of  the 
plants  in  the  latter  group  have  been  built  adjacent  to  clay  pits  in  order 
to  secure  close  coordination  between  the  clay  quarrying  and  the  manu- 
facturing plant.  Since  freight  rates  on  finished  products  are  higher 
than  on  raw  materials,  it  is  advantageous  to  locate  the  i)lant  near  the 
geogra])hical  center  of  consumption  of  finished  Avare. 

The  check  list  also  reveals  the  wdde  diversity  of  the  California 
industry  and  sliows  that  nearly  all  of  the  ceramic  products  now  in  use 
are  manufactured  wi  one  or  more  California  plants.  The  important 
excei^tions  are  magnesia  brick,  chrome  brick  and  chemical  porcelain 
and  stoneware.  Magnesia  brick  were  made  for  a  short  time  during 
the  World  War.  Avhen  foreign  supplies  were  unavailable,  and  earlier 
attempts  were  made  by  various  companies,  but  the  business  is 
uneconomic  under  normal  conditions. 


22 


DIVISION  OF   MINES  AND   MINING 


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26  DIVISION  OF    MINES   AND   MINING 

MANUFACTURING   METHODS   IN   CALIFORNIA  PLANTS. 

Common  brick:  In  California,  one  common  brick  plant  uses  the 
dry-press  process,  and  the  other  plants  are  nearly  equally  divided 
bet-u'een  the  soft-mnd  and  the  stiff-mud  process.  Nearly  all  of  the 
plants  use  drying  sheds  in  tlie  oi)en,  but  some  use  drying  racks  in  an 
enclosed  and  heated  building,  and  a  few  use  waste-heat  or  separately- 
fired  tunnel  driers.  Field  kilns  are  preferred  in  southern  California, 
where  there  is  little  rainfall  thi-oughout  the  year,  and  continuous  kilns 
of  the  Hoffman  type  are  preferred  in  northern  California.  Oil  is  the 
usual  fuel  for  the  field  kilns,  although  natural  gas  is  used  at  some 
plants  which  are  located  near  the  oil  fields.  At  some  plants,  gas  is 
used  during  the  water-smoking  period  and  oil  for  the  balance  of  the 
firing  cycle.  The  continuous  kilns  are  fired  with  coal.  Firing  tempera- 
tures range  from  cone  08  to  cone  1  (950°  to  1160°  C). 

No  mechanical  hacking,  setting  or  loading  machines  are  in  use  in 
California.  So  far  as  could  be  ascertained,  none  of  these  devices  have 
been  given  a  trial  in  the  state.  It  would  seem  that  even  though  such 
machines  in  their  present  form  may  not  be  entirely  satisfactory,  the 
hope  of  saving  from  25  to  40  man-shifts  per  100,000  brick  would  be  a 
sufficient  inducement  to  encourage  the  development  of  automatic  brick- 
handling  machines,  especially  in  the  larger  plants. 

Hollow  Mock:  All  hollow  block  are  shaped  in  auger  machines.  Some 
of  the  plants  making  hollow  block  are  also  making  common  brick  and 
both  products  are  subjected  to  the  same  drying  and  firing  treatment. 
Waste-heat  or  separately-fired  tunnel  driers  are  in  use  at  a  number  of 
l^lants.  Field  kilns  are  widely  used,  but  several  plants  use  Hoffman 
kilns,  one  uses  a  Haigh  kiln,  and  a  few  use  use  round  do-^-n-draft  kilns. 
Firing  temperatures  are  usually  between  cone  04  and  cone  3  (1060°  to 
1170° C). 

Face  hrick:  Most  of  the  face  brick  of  California  is  shaped  by  the 
stiff-mud  process.  Much  of  it  is  repressed.  The  dry-press  method  is 
used  at  a  few  important  plants.  Drying  is  usually  done  in  waste-heat 
tunnel  driers,  and  round  down-draft  kilns  are  used  at  all  plants  for 
firing.^  The  firing  temperatures  usually  approximate  cone  02  to  cone 
5  (1125°  to  1205°  C). 

Sewer  pipe:  All  sewer  pipe  is  made  in  presses  which  are  usually 
operated  by  electric  power.  Drying  is  done  on  drier  floors  which  are 
usually  heated  by  steam  or  waste  heat  from  the  kilns.  Round  down- 
draft  kilns  are  used  for  firing  and  the  firing  temperatures  range  from 
cone  02  to  cone  5  (1125°  to  1205°  C).  The  dry  strength  of  some  of 
the  sewer  pipe  mixes  in  use  in  California  is  too  low^  to  permit  setting 
to  the  full  height  of  the  kilns,  so  that  the  capacity  per  kiln  is  not  so 
great  as  at  most  of  the  eastern  plants  where  stronger  clays  are  available. 

Drain  file:  There  is  little  demand  for  drain  tile  in  California  and 
it  is  only  made  in  a  few  plants,  where  it  is  sha]ied  by  auger  machines, 
di-ied  on  heated  drying  floors  and  fired  in  round  down-draft  kilns. 

Terra  cotta:  Architectural  terra  cotta  is  an  important  product  in 
California.      A  particularly  fine  example  of  its  use  is  shown  on  the 

1  The  wide  range  of  colors  demanded  by  modern  architectural  design  is  secured  by 
varying  the  body  mixture  and  by  the  normal  differences  of  temperature  at  different 
liarts  of  tlie  kilns. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  27 

frontispiece,  Plioto  No.  1,  which  is  a  view  of  the  Kuss  Building,  in  San 
Francisco.  The  typical  body  in  use  in  California  consists  of  a  siliceous 
plastic  fii-eclay  mixed  with  an  equal  weight  of  nonplastics,  such  as  quartz 
sand  and  grog  made  by  regrinding  rejected  terra  cotta  from  the  i)lant. 
This  produces  a  body  liaving  an  absorption  of  about  15  per  cent,  when 
fired  to  cone  4  to  6  (1190°  to  1230°  C).  The  mixing,  pugging  and 
aging  of  tlie  body  mix  is  highly  important,  and  due  precautions  are 
taken  at  all  ])lants  1o  ensure  uniformity  of  the  plastic  mix  that  is  sent 
to  the  pressers.  All  shapes  are  made  by  hand  pressing  in  plaster  molds. 
After  drying  to  leather  liardness,  the  molds  are  stri])ped  and  the  ])ieces 
are  finished  by  hand,  after  which  they  are  dried  and  s])rayed  with 
glaze.  A  few  Carrier  humidity  driers  are  used  in  California  in  place 
of  the  usual  method  of  drying  on  heated  floors.  In  California,  the  ware 
is  fired  to  cones  4  to  6  (1190°  to  1230°  C.)  in  round  down-draft  kilns. 
A  considerable  quantity  of  garden  pottery  is  made  in  California, 
either  as  an  auxiliary  product  in  the  terra  cotta  plants  or  in  smaller 
plants  making  a  specialty  of  this  class  of  ware.  The  body  mix  and 
manufacturing  methods  are  similar  to  those  used  for  making  terra 
cotta. 

Conduits:  Electrical  conduits  are  shaped  by  auger  machines,  using  a 
mix  similar  to  that  used  for  sewer  pipe.  ]n  California,  they  are  usually 
dried  in  waste-heat  tunnel  driers.  Round  down-draft  kilns  are  used  at 
all  plants. 

Roofing  tile:  Roofing  tile  is  popular-  in  California  on  account  of  the 
l)revalence  of  KSpanish  architecture.  Hand-made  or  hand-finished 
machine  tile  is  in  considerable  demand  for  the  better  class  of  homes,  and 
machine-made  tile  is  widely  used  on  homes,  apartment  houses,  hotels, 
schools  and  even  on  office  and  public  buildings.  Most  of  the  hand-made 
roofing  tile  plants  are  small  and  have  little  equipment.  Drying  is  done 
under  sheds  or  in  a  barn,  and  firing  is  done  in  simple  rectangular  or 
vertical  kilns,  most  of  which  are  up-draft.  There  are  a  number  of 
large  plants  making  machine-made  tile  with  an  auger  machine.  Many 
of  these  use  waste-heat  tunnel  driers.  Beehive  kilns  are  in  general  use 
at  these  plants,  but  one  plant  uses  a  tunnel  kiln.  Firing  temperatures 
approximate  cones  06  to  02  (1015°  to  1125°  C).  Several  plants  pro- 
duce a  hand-finished  machine  tile  and  finish  the  upper  surface  by  hand 
before  drying  is  complete.  Such  tile  has  nearly  the  same  appearance  as 
hand-made  tile  when  laid  on  the  roof,  but  is  considerably  cheaper. 
Present-day  architectural  design  calls  for  a  wide  range  of  colors  in 
roofing  tile,  as  in  face  brick.  With  machine  tile,  the  color  range  is 
secured  by  varying  the  proportions  of  buff-  and  ])ink-burning  clays  that 
are  used  with  the  red-burning  clay  body,  and  by  sorting  the  diff'erent 
colors  produced  in  different  parts  of  the  kiln.  In  the  manufacture  of 
hand-made  tile,  the  mix  is  seldom  varied  in  a  given  plant,  but  the  color 
variations  are  obtained  by  normal  variations  in  firing  temi)erature  in 
dift'erent  i)art,s  of  the  kiln.  In  fact,  the  kilns  are  so  small  and  so  simple 
in  design  that  it  would  not  be  possible  to  secure  a  uniform  burn  of  the 
entire  kiln.  Individual  tile  usually  show  a  considerable  color  differ- 
ence between  opposite  sides  or  ends  of  the  tile.  This  feature,  together 
with  the  irregularity  of  outline,  largely  accounts  for  the  artistic  value 
of  hand-made  tile  when  applied  to  moderately  small  roofs.  It  should 
be  noted,  however,  that  hand-made  tile  can  not  be  relied  upon  to  make 


28  DIVISION   OF    MINES   AND   MINING 

a  water-proof  roof,  on  account  of  high  porosity  and  cracks  in  many  of 
the  tile.     They  are  often  laid  over  machine  tile. 

Fhie  lining:  ]\Iany  of  the  fire  brick  and  architectural  terra  cotta 
phmts  in  California  and  some  of  the  sewer  pipe  and  roofing  tile  plants 
make  flue  lining  to  supply  the  trade  within  their  marketing  territory. 
A  siliceous  refractory  mix  is  used,  similar  to  that  used  in  architectural 
terra  cotta  or  in  low  or  mediunl-duty  fire  brick.  Eound  shapes  are 
made  in  a  sewer  pipe  press,  and  square  shapes  are  made  in  an  auger 
machine  or  by  liand  pressing.  Waste-lieat  tunnel  driers  or  hiunidity 
driers  are  sometimes  used,  but  a  connuon  method  of  drying  is  on  floors 
in  heated  rooms. 

Floor  tile:  There  are  a  number  of  important  plants  in  California 
that  make  vitrified  floor  tile  by  the  dry-press  process.  Englisli  or 
Florida  kaolin  and  English,  Kentucky,  or  Tennessee  ball  clay  are 
usually  used  in  wliite  tile,  together  witli  California  or  Arizona  feldspar 
and  California  or  Nevada  silica,  although  Illinois  silica  or  Belgian  sand 
is  used  at  times  in  place  of  California  silica.  Some  plants  have  intro- 
duced California  talc  into  white  vitrified  tile  bodies  witli  considerable 
success.  Colored  tile  are  made  bj'  substituting  colored  clays  or  by 
adding  coloring  compounds  in  the  proper  proportions.  Power-driven 
presses  are  gaining  in  favor  at  the  larger  plants  for  the  shapes  and  sizes 
most  commonly  used,  but  hand-presses  are  preferred  at  the  smaller 
])lants,  and  are  used  at  all  plants  for  special,  or  infrequently  used, 
shapes.  Specially  designed  tunnel  kilns  are  in  successful  operation  at 
one  or  two  plants. 

There  has  been  a  good  market  in  California  for  rough-textured 
colored  floor  tile,  and  a  number  of  small  plants  have  been  built  to 
satisfy  the  demand.  Most  of  these  use  a  red-burning  clay,  or  a 
mixture  of  bulf-  and  red-burning  clays,  with  grog  or  siliceous  sand. 
Hand  molding  in  plaster  molds  is  extensively  practiced,  but  competition 
has  led  to  the  use  of  tile  augers  in  many  plants.  If  desired,  an  undu- 
lating surface  can  be  imparted  to  machine-made  tile  by  hand  treatment 
before  drying.  Oil  stains  are  frequently  applied  after  firing  to  modify 
the  surface  color  or  lustre  of  the  tile.  The  active  demand  for  this 
class  of  ware  in  recent  years  has  stimulated  artistic  development,  and 
the  product  from  nearly  every  plant  possesses  an  individuality  of 
design,  texture,  and  color.  In  a  few  plants,  however,  slavish  copying 
of  successful  designs  from  other  plants  was  noted. 

Wall  and  fireplace  tile:  The  artistic  development  of  California 
decorative  tile  is  an  outstanding  contribution  to  ceramic  art  in  the 
United  States.  There  is  perhaps  no  other  region  in  the  world  today 
that  produces  such  a  wide  diversity  of  wall  and  fireplace  tile,  or  that 
is  so  well  prepared  to  create  new  designs  for  private  homes,  hotels, 
stores  and  office  buildinus.  Several  factors  have  contributed  to  this 
condition,  among  which  are  the  following:  (1)  An  abundance  of  suit- 
able clays,  cheap  fuel  and  power,  and  low-unit  labor  costs  which  make 
it  possiijle  to  produce  certain  types  of  tile  so  cheaply  that  they  not 
only  find  an  important  local  market,  but  can  also  be  shipped  to  eastern 
])oints  on  a  competitive  basis.  (2)  An  active  state-wide  building  pro- 
gram that  is  based  upon  the  necessity  of  providing  for  many  new 
industries  each  vear  and  for  new  homes  for  the  thousands  of  people 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  29 

who  annually  enter  the  state  from  the  east  and  middle  west  to  become 
pennaiieiit  residents  of  California.  {'■])  The  jirevailiii^-  pi'osperity  and 
resultant  liijih  standards  of  livinji'  whieh  are  more  apj)art'nt  on  the 
J*aeific  Coast  than  in  any  other  section  of  the  United  States.  (4)  The 
diversity  of  architectural  design  arising  in  part  from  the  foregoing 
faetoi-s.  and  in  i)art  from  the  luitural  environment  of  California,  where 
climatic  conditions  favor  out-of-door  life  throughout  the  year,  and 
where  comparatively  low  land  values  in  most  residential  districts  make 
it  possible  for  a  home  builder  to  acquire  sufScient  land  to  avoid  tlie 
necessity  for  a  cramped  architectural  style  such  as  must  be  used  in 
more  congested  centers  of  population.  The  dominant  motive  of  Cali- 
fornia architecture  is  Spanish-American,  the  keynote  of  Avhich  is  to 
be  found  in  the  missions  that  were  establislied  under  Spanish  rule  in 
the  latter  part  of  the  eighteenth  and  the  first  part  of  the  nineteenth 
centuries.  Suggestetl  by  this  beginning  the  Spanish-Moorish,  ^lexican- 
Aztee,  and  Pueblo  Indian  styles  have  been  extensively  used.  Those 
desiring  a  relief  from  these  types,  yet  desiring  to  build  in  keeping  with 
their  local  surroundings,  have  often  chosen  Italian  desigiis.  Still 
others,  desiring  destinctive  effects,  and  sensing  the  possible  over- 
development of  Latin  types  in  many  districts,  have  used  New  England 
colonial,  southern  colonial,  English,  Norman,  and  other  types,  many  of 
which  are  hybrids  or  are  indistinguishable  as  formal  styles. 

Refractories:  The  manufacture  of  fire  brick  in  California  has  now 
progressed  to  the  point  where  practically  all  of  the  local  demand  for 
fireclay-  brick  and  special  shai)es  is  met  by  California  products.  Several 
manufacturers  are  making  a  fireclay  brick  with  calcined  clay  grog  that 
gives  as  good  or  better  service  as  the  best  grades  that  are  produced 
elsewhere  in  the  United  States.  The  demand  for  medium  or  low-duty 
fire  brick  is  usually  met  by  a  (luartz-grogged  fireclay  product.  One 
manufacturer  is  developing  a  flint  fireclay  brick.  Another  manufac- 
turer has  been  marketing  a  silica  brick  for  the  past  two  or  three  years. 
]\Iullite  refractories  are  being  manufactured  at  a  plant  in  Los  Angeles, 
using  cyanite  from  a  large  deposit  in  the  Imperial  Valley  desert.  No 
commercial  deposits  of  bauxite  or  diaspore  have  yet  been  discovered,  so 
that  the  state  is  still  dependent  on  eastern  products  where  a  diaspore 
brick  is  needed,  as  in  linings  for  the  hot  zone  of  cement  kilns.  How- 
ever, sufficient  ((uantities  of  bone  clay  have  been  found  on  several 
properties  in  southern  California  to  permit  its  use  as  calcined  grog 
and  as  a  portion  of  the  plastic  content  in  the  manufacture  of  high- 
alumina  brick. 

The  methods  of  manufacturing  refractory  ware  in  California  follow 
the  usual  practices  employed  elsewhere.  Most  plants  are  equipped 
with  auger  machines  for  shaping  the  standard  shapes.  The  better 
grades  of  brick  are  repressed.  Some  hand-molded  standard  brick  are 
made,  and  are  re])ressed  in  hand-operated  presses.  Special  shapes  are 
made  bv  hand-molding.  Drving  is  nsuallv  done  in  waste-heat  tunnel 
driers,  although  a  few  humidity  driers  are  in  use,  especially  for  the 
shapes  that  are  difficult  to  dry.  Round  down-draft  kilns  are  generally 
used  for  firing,  and  the  firing  temperature  for  most  of  the  fireclay  brick 
produced  in  the  state  is  cone  11  (1325°  C).  One  of  the  most  notable 
developments  is  the  use  of  a  tunnel  kiln  by  the  Vitrefrax  company  for 
firing  mnllite  brick  at  cone  29  (1640°  C). 


30  DIVISION  OF    MINES   AND   MINING 

Tableware:  Plain  and  decorated  .semi-vitreous  table  and  hotel  ware 
is  made  at  a  number  of  plants  in  California.  Thus  far,  these  ])lants 
have  used  imported  clays,  in  conjunction  with  feldspar  and  silica  from 
local  sources.  One  ])lant,  the  Empire  China  Company,  expects  to  j>o 
into  production  in  tlie  spring  of  1928  on  vitreous  ware,  using  a  Cali- 
fornia feldspar  and  silica  and  a  Nevada  china  clay,  together  with  a 
certain  amount  of  Florida  clay.'^  The  manufacturing  methods  follow 
Well-established  practice. 

Kitche7i  ware  and  sionewarc:  A  number  of  potteries  in  California 
are  nuuuifacturing  kitchen  ware  antl  stoneware.  In  most  cases,  all 
materials  used  in  the  body  mix  are  obtained  from  local  sources  of 
supply.  Slip  clays  for  glazing  have  thus  far  been  imported  from 
other  states.     The  usual  manufacturing  practices  are  followed. 

Art  pottery:  There  are  a  few  small  potteries  devoted  to  the  produc- 
tion of  distinctive  lines  of  art  pottery.  As  the  type  of  body  and  the 
plant  practice  is  different  at  each  of  these,  the  reader  is  referred  to  the 
check  list,  figure  1,  and  to  the  plant  descriptions  in  Chapter  III  for 
further  details. 

Red  earthenware:  The  local  demand  for  flower  pots,  ollas,  earthen- 
ware household  utensils  and  other  red  earthenware  products  is  met  by 
a  number  of  plants,  some  of  which  specialize  in  one  or  more  of  these 
products. 

Sanitarij  ware:  A  complete  line  of  sanitary  porcelain,  with  the  excep- 
tion of  bath  tubs,  is  made  at  three  plants  in  California  by  the  casting 
process,  using  imported  clays,  California  or  Illinois  silica,  and  Cali- 
fornia feldspar.  All  three  plants  are  e([ui]iped  with  tunnel  kilns  for 
both  the  biscuit  and  glost  firing.  Biscuit  firing  is  usuallv  at  cone  11 
(1325°C.),  and  the  glost  firing  is  at  cone  6  (1230°  C).  'Three  metal 
enameling  plants  are  devoted  to  the  manufacture  of  enameled  cast-iron 
sanitary  ware.  Semi-porcelain  plumbing  accessories  are  made  at  three 
smaller  plants.  One  of  these  uses  a  body  made  entirely  from  California 
raw  materials. 

Electrical  insulators:  The  manufacture  of  high-tension  electrical 
insulators  probably  presents  one  of  the  most  difficult  ceramic  ]iroblems 
of  modern  industry.  The  industry  is  rppresented  in  California  by  one 
plant,  that  of  the  Westinghouse  Electric  and  Manufacturing  Comjiany, 
at  Emeryville  (c.v.,  p.  45).  California  feldspar  is  the  only  local 
material  used  in  the  body  mix.  Semi-])oi-celain  electrical  accessories  are 
being  made  at  three  small  plants  in  California. 

Thermal  insulators:  Although  accurate  statistics  are  unavailable  for 
publication,  the  bulk  of  the  diatomaceous  earth  insulating  brick  output 
of  the  United  States,  if  not  of  the  world,  is  produced  in  California. 
The  Celite  Products  Company  at  Lompoc,  and  the  Stockton  Fire  Brick 
Company  at  Stockton  are  the  only  producers  at  present.  The  produc- 
tion of  sawn  natural  blocks  of  diatomaceous  earth,  at  one  time  of 
importance,  is  now  relatively  small  compared  to  the  production  of 
molded  (hand  or  auger-machine)  and  fired  shapes. 


'Personal  communication  from  G.  Ray  Boggs,  December  8,  1927. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  31 

STAT  I  ST  J  ('S. 
BRICK   AND   HOLLOW   TILE. 

The  briek  and  hollow  tile  statistics  compiled  by  the  State  Division  of 
Mines  and  Alining  inelnde  all  classes  of  brick.  The  detailed  figures  of 
production  and  value  for  1926,  by  counties  and  by  class  of  ware,  are 
given  in  Table  2.  This  is  a  com])anion  to  Table  6,  referred  to  later 
under  pottery  clay,  in  which  the  segregated  figures  for  other  clay 
products  are  given. 

Table  3  gives  statistics  for  the  common  brick  industry  of  California, 
by  y(>ars  from  1896  to  1926  inclusive.  The  annual  value  of  the  com- 
mon brick  production  is  plotted  to  a  ratio  .scale  ou  Tlate  II.  For  com- 
parative purposes,  Plate  II  also  includes  the  curves  for  the  average 
unit  value  of  common  brick  per  thousand,  and  the  gross  annual 
value  and  the  average  unit  value  per  barrel  for  cement  during  the 
same  period.  The  rapid  growth  of  the  cement  industry  relative  to  that 
of  the  common  brick  industry  is  of  special  interest,  as  is  also  the 
comparative  trend  of  prices  in  the  two  industries.  The  trend  of  cement 
prices  reflects  the  economies  of  steady  technical  and  mechanical  prog- 
ress in  the  cement  industry,  and  the  increasing  size  of  plant  units.  The 
trend  of  common  brick  prices  closely  parallels  the  fluctuations  in  com- 
modity prices  and  labor  wages,  as  modified  by  fluctuations  in  the  unit 
cost  of  fuel,  as  a  high  percentage  of  the  cost  of  making  common  brick 
arises  from  labor  and  fuel  costs,  and  there  have  been  no  im])ortant 
technical  or  mechanical  improvements  in  brick  manufacture  during 
the  period  under  review.  The  influence  of  the  San  Francisco  earth- 
quake of  1906  is  strikingly  shown  by  the  decline  of  the  common  brick 
])roduction  and  the  continued  rise  of  the  cement  jn-oduction  after  a 
slight  recession  following  the  financial  panic  of  1907. 

POTTERY  CLAY. 

The  term  'pottery  clay'  as  used  in  State  Mining  Bureau  reports 
refers  to  all  clay  other  than  that  used  in  the  manufacture  of  common 
brick  and  liollow  tilc.^  The  production  of  pottery  clay  in  California  in 
1926  is  given  in  Table  4,  and  the  production  by  years,  from  1887  to 
1926,  inclusive,  is  given  in  Table  5.  The  production  of  pottery  clay 
products  in  California  during  1926  is  given  in  Table  6. 

'For  a  further  elaboration  of  this  definition  see  Cal.  State  Min.  Bur.  Bulletin  No. 
97,  p.  94,  192(i,  or  other  annual  statistical  reixirts  Iiy  the   Bureau. 


82 


DIVISION   OF    MINES   AXD   MIXING 


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7.14 

7.35 

7,18 

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7.32 

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3;] 


TABLE    No.  3. 

Common  Brick  Production  of  California,  by  Years.* 

Production  Av.  value 

Year  M  Value      per  M 

ISyb 74,240  $391,567  ?6.H 

1897 88.890  509,955  5.74 

1898 108,076  598,823  5.54 

1899 : 129,512  800,210  6.18 

1900 119,906  698,583  5.83 

1901 146,522  943,250  6.44 

1902 181,040  1,291,941  7.14 

19U3 217,715  1,600,882  7.35 

1904 256,898  1,843,936  7,18 

1905 284,205  1,961,909  6.90 

1906 278,780  1,962,866  7.05 

1907 339,439  2,483,062  7.32 

1908 236,383  1,593,814  6.74 

1909 276,396  1.749,209  6.33 

1910 280,265  1,694,312  6.05 

1911 282,199  1,716,442  6.08 

1912 349,797  2,198,303  6.28 

1913 295,729  1,699,426  5.75 

1914 221,243  1,356,885  6.13 

1915 160,452  981,888  6.12 

1916 168,826  1,107,940  6.56 

1917 169,045  1,207,765  7.14 

i:tl8 96,732  912,205  9.43 

i:tl9 126,892  1,545,558  12.18 

l;(20 163,782  2,823,304  17.24 

1921 202,417  2,880,124  14.21 

1922 323,625  4,363,629  13.48 

1923 397,754  5,194.527  13.03 

1924 335,203  4,124,385  12.30 

1925 297,449  3,317,766  11.12 

1926 328,664  3,231,597  9.82 

•Data  prior  to  1920   from  U.   S.  Geol.   Surv.  Min.  Res.,  since  1920   from  Cal.   State 
Min.   Bui'can   repf>rts. 

TABLE    No.  4. 

Production   of   Pottery   Clay    in   California    in    1926. 

(From  State  Div.  Mines  and  Mg.  Bulletin  No.  100,  p.  97,  1927.) 

Ciiunty  Tons  Value  Used  in  the  manufacture  of 

Alani(_-da     5,870  $7,183        Drain,    faience,    flood,    quarry   and   roofing 

tile,  sewer  pipe. 

.A.mador 97,768  135,767        Architectural    terra    cotta,    fire    clay   prod- 

ucts, chimney  and  sewer  pipe,  refracto- 
ries, drain,  floor  and  roofing  tile,  and 
various. 

Ciiniia   Costa 7,675  5,688       Architectural    terra    cotta,    sewer    pipe, 

faience  and  drain  tile. 

Los  Angeles a86,767  99,076       Architectural    terra    cotta,    conduit,    red 

earthenware,  refractories,  drain,  faience, 
floor  and  roofing  tile,  chimney  and  sewer 
pipe,  and  oil  well  mudding. 

Monterey 491  1,164        Floor  and  roofing  tile. 

Orange     13,150  38,989       Conduit  pipe  and  stoneware,   refractories, 

di-ain  and  roofing  tile,  and  various. 

Placer     104,250  147,241       Arcliitectural    terra   cotta,   chimney,   .sewer 

and  conduit  pipe,  drain,,  floor  and  rf)of- 
ing  tile,  sanitary  ware,  red  earthenware, 
and  various. 

Jliverside     58,528        >    178,383       Conduit  and  sewer  pipe,  red  earthenware, 

refractories,  roofing  tile,  and  various. 

.'^acramento     1,548  2,310       Crushed  brick,  faience  tile,  et  al. 

San  IJernardino  __         ''2,268  10,605        Porcelain. 

San   Diego '•130,187  58,269        Therapeutic  clay,  sewer  pipe,  faience,  floor 

and  roofing  tile,  and  various. 

Santa    Barbara  ___  1,100  1,700        Drain,   floor  and  roofing  tile. 

Ventura "373,000  93,250        Oil-well   drilling  mud. 

Butte,  Calaveras, 
Humboldt,  Mer- 
ced. San  Luis 
Obispo,  Santa 
Clara,   Sonoma"*        18,859  26,884       Earthenware,    porcelain,    chimney    and 

„  sewer  pipe,  drain  and  roofing  tile. 

Totals     801,461  $806,509 

*  Combined  to  conceal  output  of  a  single  operator  in  each. 
=>  Includes  clay  and  shale  for  oil-well  drilling  mud. 

''  Includes  kaolin. 

"■  Includes   'Cornwall'  stone. 

*  Includes  therapeutic  clay. 

3 — 54979 


34  DIVISION'   OF    MIXES  AXD    :MIXIX0 

TABLE    No.  5 

Pottery  Clay   Production  of  California,  by  Years. 

(From  Slate  Div.  Mines  and  Mg.  Bulletin  Xo.  100,  i>.  98,  1927.) 

Year                                  Tons  Value  Vear  Tons  Value 

1887 75,000  $37,500  i:i07 160,385  $254,454 

1888 75,000  37,500  IKOS 208,042  325,147 

1889 75,000  37,500  1909 299,424  4G5,647 

1890 100,000  50,000  1910 249,028  324,099 

1891 100,000  50,000  1911 224,756  252,759 

1892 100,000  50,000  1912 199.605  215,683 

1893 24,856  67,284  1913 231,179  261,273 

1894 28,475  35,073  1914 179,948  167,552 

1895 37,660  39,685  1915 157.866  133,724 

1896 41,907  62,900  1916 134,636  146,538 

1897 24,592  30,290  1917 166.298  154,602 

1898 28,947  33,747  1918 112,423  166,788 

1899 40,600  42.700  1919 135,708  245,019 

1900 59,636  60,956  1920 203,997  440,689 

1901 55,679  39,144  1921 225,120  362,172 

1902 67,933  74,163  1922 277,232  473,184 

1903 90,972  99,907  1923 376,863  697,841 

1904 84,149  81,952  1924 417,928  651,857 

1905 133,805  130,146  1925 537,587  674.376 

1906 167,267  162,283  1926 801,461  806,509 


Totals 6.710.784  $8,442,643 

TABLE    No.  6. 

Value   of   Pottery   Clay    Products    Made    in    California    During    1926. 

(From  State  Div.  Mines  and  Mg.  Bulletin  Xo.  100,  p.  97,  1927.) 

X-imber  of 
Product  p.oducers      Tons  Value 

Architectural  terra  cotta 5  15,954  $2,361,524 

Chimney  pipe,  terra  cotta  and  flue  lining 10  13,207  461,786 

Drain    tile 12  7.17S  113.168 

Roofing   tile    21  73.9S4  1.917,415 

Sewer    pipe     10  100.689  2.910,567 

Ohinaware  and  semi-vitreous  tableware 3  627,516 

Sanitary    ware    6  1,894.705 

Red   earthenware 6 198,308 

Stoneware   and  chemical  stoneware 6  434,772 

Floor,   faience,   mantel,   glazed   and  hand-made  tile 27  2,867,772 

Miscellaneous    art    pottery,     bisque    ware,     brick    dust, 

calcined    clay,    ceramic,    mosaic    wall    tiles,    conduit, 

conduit   pipe,    fire    clay   products,    crushed    brick    and 

tile,  garden   furniture  and  pottery,   high   temperaturt- 

cement,     porcelain,     gas    radiants,     and     backs,     cast 

stone,    ground   clay,    fire    clay    and    grog,    broken    tile 

and    various    23  837.670 


$14,625,203 


CLAY  RESOURCES  AND  CERAMIC   INDUSTRY  35 


TOTAL    ANNUAL    VALUE    OF    CLAY    PRODUCTS    IN    CALIFORNIA    COM- 
PARED TO  THE  TOTAL  FOR  THE  UNITED  STATES. 

The  figureis  of  the  annual  value  of  clay  products,  and  the  number  of 
producers  reporting  are  given  in  Table  7,  for  California  and  for  the 
entire  United  States  during  the  period  from  1896  to  1926.  inclusive.  The 
ranking  of  California  auu)ng  the  states,  and  the  production  of  Cali- 
fornia as  a  percentage  of  the  total  United  States  production  are  also 
shown  in  the  table.  The  production  tigures  are  i)lotted  on  a  ratio  scale 
on  Plate  111.  Both  the  California  and  tlie  United  States  curves  may  be 
conveniently  divided  into  four  time  periods:  (1)  From  1896  to  1907, 
a  period  of  rapid  growth,  during  Avhich  the  United  States  ])roduction 
increased  at  an  average  of  8.7  per  cent  per  year,  whereas  the  California 
l)roduction  increased  at  an  average  of  21.3  per  cent  per  year.  (2) 
From  1907  to  1915,  a  period  of  dei)ression  following  the  financial  panic 
of  1907,  the  effect  of  which  was  exaggerated  in  its  influence  on  the 
common  brick  and  hollow  tile  industry  of  California  by  the  San  Fran- 
cisco earthcjuake  of  April,  1906.  During  this  period  the  average 
annual  production  of  clay  products  in  the  United  States  remained 
nearlv  stationary,  while  that  of  California  showed  an  average  annual 
decrease  of  5.7  per  cent.  A  contributing  factor  to  this  condition,  both 
in  California  and  in  the  United  States  at  large,  was  the  ra])id  increase 
in  the  use  of  reinforced  concrete,  especially  in  the  construction  of  large 
buildings  in  the  major  cities.  (3)  From  1915  to  1923,  a  period  of 
rajiid  expansion  and  rising. prices,  but  with  a  retardation  of  growth  in 
1917  and  1918  in  the  ])roduction  of  certain  ceramic  branches,  such  as 
architectural  terra  cotta,  which  were  classed  as  nonessential  and  were 
unable  to  secure  sufficient  fuel  or  labor  for  maximum  production,  and 
a  further  period  of  retardation  in  1921,  following  the  post-war  deflation 
that  gained  momentum  in  1920.  The  latter  effect  is  not  noticed  in  the 
ceramic  production  of  California.  The  average  annual  increase  in  the 
value  of  ceramic  products  in  the  United  States  during  the  eight  year 
period  was  12.7  per  cent  compared  to  24.6  per  cent  for  California.  (4) 
From  1923  to  1926.  Tlu'  {)eriod  is  too  short  to  permit  accurate  interpre- 
tation of  trend,  but  a  slowing  down  is  apparent,  both  in  California  and 
in  the  United  States  at  large. 

The  average  annual  rate  of  growth  of  the  value  of  ceramic  products 
in  the  United  States  for  the  entire  period  of  30  years  from  1896  to 
1926  was  6.0  per  cent,  compared  to  12.3  per  cent  for  California. 


no 


DIVISION   OF    MINES   AND   MINING 


TABLE   No.  7. 

California    and   Total    United    States    Production    of   Ceramic    Products 

from  1896  to  1926.* 

California  United  States 

No.  Raik  'U  uf                                             Number 

of  i>r(>-  anijnji          total                                                    of 

Years                                 Value            ducers  states    l^.  S.  value  Value            producers 

1S9C $680,207                91  21  1.08  $6;',, 110, 408  629,3 

1897 703,410                92  21  1.13  62,359,991  5424 

1898 1,263,734                77  12  1.70  74,487,680  5971 

1899 1,587,518               79  12  1.66  95,797,370  6962 

1900 1,375,998               72  14  1.43  96,212,345  G375 

1901 1,769,155               92  11  1.61  110,211,587  6421 

1902 2,253,096                89  11  1.84  122,169,531  6045 

1!I03 2,831,543             105  9  -2.16  131,062,421  6034 

i:t04 3,624,734             121  8  2.77  131,023,248  6108 

191)5 3,865,147             122  8  2.58  149,697,188  5925 

1906 4,364,230             113  8  2.71  161,032,722  5857 

1907 5,740,537             118  8  3.61  158,942,369  5536 

1908 4,523,745             119  8  3.40  133,197,762  5328 

1909 4,437,165                99  9  2.67  166,321,213  5068 

1910 4,842,391             107  9  2.85  170,115,974  4915 

lilll 4,915,866                92  8  3.03  162,236,181  4628 

1112 5,912,450                91  8  3.42  172,811,275  4284 

1913 5,344,958                91  9  2.95  181,289,132  4065 

1914 4,461,661                84  10  2.70  164,986,983  3860 

1915 3,599,375                83  10  2.21  163,120,232  3636 

1916 4,163,426                79  10  2.01  207,260,091  3412 

1917 4,826,125                74  11  2.10  232,512,773  3153 

11)18 4,329,220                68  11  2.00  221,884,651  2783 

1919 5,834,648                66  10  2.10  275,346,378  2776 

1920 10,946,423                65  9  2.9  373,670,102  271G 

l!)21 11,172,491                63  8  4.1  270,738,536  2449 

1>)22 14,689,830                62  6  4.6  321.494,403  2098 

1923 20,833,053                86  6  4.9  424,582,628  2441 

1924 20,994,732                86  (i  5.0  415,779,378  2353 

1925 21,324,844                99  6  5.0  423,446,917  2417 

1926 21,651,327                95  _  4.6  459,049,470  2391 

*  Prom  U.  R.  Geol.  Survey  prior  to  1920.      Since  1920  from  U.  S.  Bur.  Mines,  Min. 
Res. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


37 


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38  DIVISION  OF   MINES   AND   MINING 

Chapter  III. 
CLAY  DEPOSITS  AND  CERAMIC  PLANTS  BY  COUNTIES. 


ALAMEDA   COUNTY. 
General    Features. 

Alameda  County  is  on  the  eastern  shore  of  San  Francisco  Bay  and 
has  a  land  area  of  732  square  miles,  500  of  which  are  ricli  agricultural 
bottom  lands  devoted  to  farmini>-  and  fruit  growing-.  The  princijial 
cities  are  Oakland,  Alameda  and  Berkeley.  The  population  of  the 
county  is  344,177  (1920  census). 

The  county  is  traversed  in  a  northwesterly  and  southeasterly  direc- 
tion by  several  mountain  ranges,  which  together  form  the  eastern  grouj) 
of  the  Coast  Range  mountains.  These  ranges  become  rugged  and  reach 
higher  altitudes  in  the  southeastern  portion  of  the  county,  their  con- 
tinuation into  Santa  Clara  County  culminating  in  the  ]Mount  Hamilton 
range.  The  mountains  consist  largely  of  metamorphic  sandstones, 
jaspers  and  serpentines  of  the  Franciscan  formation,  together  with 
sandstones  and  shales  of  Cretaceous  and  Tertiary  age. 

The  mineral  resources  of  Alameda  County  include  asbestos,  brick, 
chromite,  clay,  coal,  limestone,  magnesite,  manganese,  potash,  pyrite, 
salt,  soapstone,  and  crushed  rock,  sand  and  gravel.  The  principal  com- 
mercial mineral  products  in  the  order  of  their  relative  importance  are : 
miscellaneous  stone,  salt,  brick  and  hollow  tile. 

Clay    Resources. 

There  are  excellent  deposits  of  common  clay  suitable  for  the  manu- 
facture of  common  brick,  hollow  tile,  and  roofing  tile  at  various  places 
in  the  county,  and  a  number  of  i)lants  for  manufacturing  these  products 
are  in  operation.  The  best  and  most  extensive  common  clay  deposits 
occur  in  the  Livermore  and  Niles  valleys. 

High-grade  clays  were  at  one  time  mined  near  Tesla,  on  the  eastern 
edge  of  the  county,  but  there  is  no  present  production. 

On  account  of  favorable  manufacturing  and  marketing  conditions, 
a  number  of  important  ceramic  plants  have  been  established  in  the 
county,  especially  in  Oakland,  Alameda,  Berkeley,  Niles  and  Livermore, 
and  a  wide  diversity  of  ceramic  ware  is  produced. 

California  Bisque  Doll  Companii.  Mrs.  H.  T.  Epperson,  manager. 
Office  and  plant  at  1175  San  Pablo  Avenue,  Berkeley.  Formerly  the 
California  China  Company.  This  plant  was  built  in  1906  for  the 
manufacture  of  bisque  doll  heads,  but  there  was  no  commercial  output 
until  1919.  It  is  said  to  be  the  only  plant  in  the  TTnited  States  produc- 
ing bisque  doll  heads  on  a  commercial  scale.  A  number  of  other  ceramic 
products  are  made,  such  as  salt  and  pepper  shakers,  art  vases  and  bowls, 
and  novelties.  California  raw  materials  are  used  whenever  possible. 
The  use  of  Clark  and  IMarsh  kaolin  from  near  Cali.stoga  (samples  No. 
] 90-192,  pp.  261,  280)  is  of  special  interest.  The  clays  are  prepared  by 
small  scale  apparatus,  and  most  of  the  shapes  are  made  by  casting. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  39 

Fii"iii^'  is  (lone  in  safrgors  in  a  small  np-di'ai't  kiln,  firetl  to  cone  12  for 
biscuit  ware,  and  to  cone  7  to  [)  for  the  g:lost  firin<r. 

Bibl:  Cal.  State  Min.   P.nr.  Prel.  Ropt.  No.  7,   |).  35   (California 
China  Company). 

California  Faience  Company  (formerly  The  Tile  Shop).  C.  1\. 
Thomas  and  "W.  B.  Brap-don.  owners  and  operators,  133")  Hearst 
Avenue.  Berkeley.  At  this  ])laiit.  jilazed  art  pottery,  art  tile,  and 
inserts  are  made  from  a  re(l-l)ui'nin<i:  body,  the  composition  of  which 
\aries  from  time  to  tinu%  depeiulin<i'  upon  the  clays  that  are  available. 
Shale  is  purchased  from  the  Riehmoiid  Pressed  Brick  Co.  (sample  No. 
110,  ]).  325),  and  clay  is  somelimes  obtaiiu'd  from  the  Angel  Ranch 
deposit  near  Eureka    (sam])le  No.  ISl,  p.  336). 

The  clays  are  prepared  by  ball-millinpf,  and  are  pup:j2:ed  by  hand. 
IMost  of  tlie  art  pottery  is  shapped  by  castinfj,  and  the  tile  and  decoi-a- 
tive  inserts  are  made  by  hand  ]iressing  in  plaster  molds.  A  p:as-fired 
pie-bakinp:  oven  is  used  to  finish  the  dryinp:,  after  air-dryinj;  is  com- 
])leted  in  the  shop. 

Two  hilns  are  in  use.  One  is  a  Calkins  kiln,  and  the  other  is  a  round 
down-draft  kiln,  13-ft.  in  diameter  and  lO-ft.  high,  wdth  a  continuous 
bag-wall  extending  nearly  to  the  crown.  The  biscuit  and  glaze  firing 
are  done  together,  the  kilns  being  set  so  that  the  w^are  to  be  biscuited 
receives  the  greater  heat.  Cone  04  is  brought  down  in  the  biscuit 
zone  of  the  kilns. 

The  company  has  been  successful  in  establishing  a  small,  but  high- 
cla.ss  market  for  its  ware,  and  a  considerable  part  of  its  output  is 
shipped  to  Eastern  points.  Special  orders  are  taken  for  ornamental 
garden  and  fountain  pieces,  as  well  as  for  pottery  and  tile. 

Two  or  three  men  are  employed  in  addition  to  the  owners. 

Bibl :  Cal.  State  :\rin.  Bur.  Prel.  Rept.  No.  7,  p.  37. 

California  Pottery  Company.  P.  A.  Costello,  president ;  J.  P.  Cree- 
gan,  secretary.  Plant,  2265  East  Twelfth  Street,  Oakland.  (The  com- 
pany also  o]ierates  a  ])lant  at  ^Merced,  see  ])age  12S.)  This  company  was 
established  in  1872.  The  products  made  at  this  factory  are  vitrified 
sewer  pipe,  chimney  pipe,  flue  lining,  garden  pottery,  lead  pots  for 
Ihe  paint  industi-y,  wall  and  floor  tile  (faience),  roof  tile,  and  stone- 
ware. Th(>  clays  used  are  Lincoln  No.  1-6  (sami)le  No.  146.  p.  303), 
lone  sand  (Shepard)  (sample  No.  128,  p.  261),  Valley  Springs  clay 
(samples  No.  202-204,  pp.  299,  337),  a  surface  clay  from  Niles,  similar 
1o  that  used  by  the  Niles  plant  of  the  W.  S.  Dickey  Clay  Manufacturing 
<'().  (sam])le  No.  265,  p.  343),  and  some  Nigger  Ilill  clav  from  Calaveras 
County  (sample  No.  236,  p.  263). 

The  sewer  pipe,  chimney  pipe,  flue  lining  and  garden  pottery  and 
1  ile  mixtures  are  prepared  by  dry-pan  grinding,  followed  by  wet-pan 
pugging.  Sewer  pipe  is  made  in  the  usual  presses.  Chimney  pipe, 
flue  lining,  and  roofing  tile  are  also  made  in  a  sewer-pipe  press.  Some 
of  the  roofing  tile  are  hand  finished,  giving  the  appearance  of  hand- 
made tile.  Floor  tile,  wall  tile,  and  garden  pottery  are  hand  molded. 
Single-fire  glazes  are  used. 

The  clay  mixture  for  stoneware  is  prepared  by  blunging,  filter  press- 
ing and  pugging,  followed  by  ageing  for  a  suitable  period.  Most  of 
the  stoneware  is  jiggered. 


40  DIVISION  OF   MINES  AND   MINING 

Diying  is  done  iii  a  steam  rack  for  the  tile  and  stoueware,  and  other 
ware  is  dried  on  floors  heated  with  waste  heat  from  the  kilns. 

Eight  round  down-draft  kilns  are  used,  fired  with  oil,  atomized  with 
steam.  Two  or  three  are  30-ft.,  four  are  28-ft.  and  two  are  25-ft.  in 
diameter.  Stoneware  is  fired  to  cone  8  (2400°  F.  on  pyrometer)  and 
other  ware  is  fired  to  2100°  F.  The  average  firing  time  is  four  days, 
making  the  total  cycle  8  to  9  days  per  kibi.     Sixty  men  are  employed. 

In  1927,  this  company  purchased  the  property  formerly  operated  by 
the  California  Pressed  Brick  Company,  and  the  plant  was  overhauled 
and  newly  equipped  for  the  manufacture  of  brick  and  tile.^ 

Bibl :  Cal.  State  Min.  Bur.,  Bull.  No.  38,  p.  202 ;  Prel.  Kept.  No. 
7,  p.  36. 

N.  Clark  and  Sons.  A.  V.  Clark,  president  and  general  manager ;  G. 
D.  Clark,  secretary.  Main  office  at  112-116  Natoma  Street,  San  Fran- 
cisco. Plant  at  Pacific  Avenue  and  Fourth  Street,  Alameda.  This 
plant  has  been  in  operation  since  1889.  The  principal  products  are 
architectural  terra  cotta,  sewer  pipe,  fire  brick  and  face  brick. 

The  company  owns  or  controls  deposits  of  all  raw  materials  used  in 
the  body  mixes  at  the  plant.  Sand  and  clay  from  lone  (see  under 
Amador  County)  and  a  calcareous  shale  from  a  deposit  at  Walnut 
Creek  (see  under  Contra  Costa  County)  are  the  principal  materials 
used. 

The  fire  brick  and  face  brick  are  made  by  the  stiff-mud  process, 
without  repressing.  Sewer  pipe  and  terra  cotta  are  made  by  the  usual 
processes.  Sixteen  oil-fired  round  down-draft  and  muffle  kilns  are 
in  use. 

Part  of  the  plant  was  destroyed  by  fire  in  July,  1917,  but  was  rebuilt 
in  1919.  Another  fire  occurred  on  September  16,  1927,  which  caused  a 
shut-down  during  reconstruction. 

Bibl :  State  Min.  Bur.  Bull.  38,  p.  202 ;  Prel.  Kept.  7,  p.  36. 

W.  S.  Dickey  Clay  Manufacturing  Company:  N.  A.  Dickey,  manager. 
Office,  604  Mission  Street,  San  Francisco.  Plant  No.  18  is  one  mile  west 
of  Niles,  and  was  formerly  known  as  the  California  Brick  Company. 
Hollow  tile  and  paving  brick  are  manufactured.  A  Haigh  continu- 
ous kiln  is  used  for  firing.  Plant  No.  19  is  at  Livermore,  and  was  for- 
merly known  as  the  Livermore  Firebrick  Works.  Fire  brick,  fireclay 
refractories,  face  brick  and  sewer  brick  are  manufactured. 

The  management  refused  permission  to  publish  data  on  the  two 
plants,  and  as  much  of  the  data  previously  published  by  the  Bureau  is 
obsolete,  there  is  no  need  for  repeating  it  here. 

Bibl:  Cal.  State  Min.  Bur.  Prel.  Kept.  No.  7.  p.  35   (California 
Brick  Company),  and  p.  37  (Livermore  Firebrick  Works). 

ElectHcal  Porcelain  Works.  Levi  S.  Baker,  proprietor;  Joseph  Baker 
and  Chas.  Ball,  officials.  Office  and  plant  at  2414-16  Sixth  Street, 
Berkeley.  Electrical  porcelain  insulating  products  are  manufactured, 
using  English  china  and  ball  clays,  Florida  kaolin,  San  Diego  County 
feldspar  and  silica,  and  lone  and  Lincoln  fireclays.  The  ware  is 
shaped  by  dry  pressing,  throwing,  turning,  machine-pressing,  or  cast- 
ing, according  to  the  nature  of  the  shapes  to  be  made.     Two  oil-fired 

'  Clay -Worker,  July,  1927,  p.  36. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  41 

kiln.s  are  used.     One  is  14  feet  in  diameter,  and  tlie  other  is  8  by  8  feet 
square. 

Hidecker  Tile  Company.  G.  C.  liidecker,  manager.  The  plant  is 
at  Twenty-fourth  and  Union  streets,  Oaldand,  and  manufactures  roof- 
ing tile  only.  Local  clay  from  excavations  in  Oakland  and  vicinity 
is  mixed  with  Lincoln  chiy  (samjile  No.  147,  p.  ;]03)  and  Natoma  clay 
(samples  No.  210  and  212,  p.  337).  A  Williams  hammer  pulverizer  is 
u.sed  to  disintegrate  the  clay,  which  is  then  screened  through  an  8-mesh 
screen,  passed  to  a  pug-mill,  and  finally  to  an  auger  machine,  which 
is  equipped  Avith  a  hand-operated  wire-cutter.  The  tile  are  dried  on 
pallets  in  the  open  air. 

Two  up-draft  oil-fired  kilns  are  used.  The  larger  of  these  holds 
25,000  eighteen-inch  tile,  and  the  smaller  holds  12,000  tile.  The  water 
smoking  is  done  with  wood-shavings  and  requires  24  hours.  This  is 
followed  by  four  days  firing  with  oil,  to  a  finishing  temperature  ranging 
from  875°  to  980°  C.  Plight  to  ten  men  are  employed  during  the 
operating  season  of  five  to  eight  months. 

Kraft  Tile  Company.  A.  Clay  Myers,  in-esident;  J.  L.  Kraft,  C.  H. 
Kraft,  E.  Ridgeway,  and  II.  E.  Leash,  directors  and  officers.  General 
office,  55  New  ^Montgomery  Street,  San  Francisco.  Plant  at  Pabrico, 
two  miles  west  of  Niles. 

This  plant  was  built  in  1926  to  manufacture  high-fired  faience  tile, 
using  Lincoln  fireclay  and  lone  sand.  Augers  are  used  for  shaping  the 
tile.  Hot-air  driers  of  the  deliydrator  tyi)e  are  used  for  drying. 
After  drying,  the  tile  are  carefully  trimmed  to  size  in  a  special  machine 
before  applying  the  glazes.  This  produces  a  finished  tile  that  falls 
within  closer  limits  of  size  than  is  customary  in  most  plants.  The 
product  is  fired  in  round  down-draft  kilns.  The  output  of  the  plant 
in  July,  1927,  was  1000  square  feet  of  tile  daily. 

Miller's  OaMand  Art  Pottery.  ]\Irs.  Isabelle  Miller  Burress,  owner. 
Albert  Van  Cleve,  manager,  2237  East  Twelfth  Street,  Oakland.  Sewer 
pipe,  patent  chimney  pipe,  flue  lining,  and  drain  tile  are  made  at  this 
])lant.  Yarn  and  Harvey  clays  (sam]>les  No.  124  and  133,  pp.  298,  302) 
from  M.  J.  Bacon,  lone,  are  used,  together  with  excavation  debris  from 
Oakland  and  vicinity. 

The  clays  are  prepared  in  dry  and  wet  pans,  and  the  ware  is  shaped 
in  steam  presses.  Drying  is  done  on  the  floors  of  the  building,  without 
special  provision  for  heating  by  waste  kiln  gases. 

The  firing  equipment  consists  of  five  oil-fired  round  doAvn-draft  kilns, 
the  largest  of  which  are  22-ft.  in  diameter  and  hold  35  tons  of  ware. 
The  firing  schedule  varies  from  48  to  72  hours,  depending  on  the  ware, 
and  the  finishinc-  temperature  averages  2000°  P.  (1093°  C.)  with  a 
maximum  of  2100°  F.  (1149°  C). 

Twenty-five  men  are  employed. 

Bibl:   Cal.   State  Min.  Bur.,  Bull.   No.   38,  p.   204    (Oakland  Art 

Pottery). 

M  &  S  Tile  Company.  Owned  by  F.  J.  Thomas,  G.  L.  Smith  and 
J.  ]\I.  Bettencourt.  The  plant  is  near  the  Oakland-Niles  highway  at 
Decoto.  This  plant  was  established  in  February,  1926,  for  the  manu- 
facture of  hand-made  roofing  tile.     A  local  surface  clay  (sample  No, 


42  DIVISION   OF    MINES  AND   MINING 

264,  ]x  848)   is  used.     Tlie  clay  is  similar  to  that  used  in  the  W.   S. 
Dickey  Company's  hollow  tile  i)lant  at  Xiles  (sample  Xo.  265,  j).  843). 

The  clay  is  mined  -with  the  aid  of  a  team  and  scraper.  A  small  power- 
driven  pug-mill  prepares  the  clay  for  hand-molding.  Drying  is  done 
on  pallets  under  a  shed.  A  rectangular  oil-fired  down-draft  kiln,  having 
a  capacity  of  5700  roofing  tile,  is  used  for  firing.  The  firing  schedule 
occupies  55  to  60  hours,  and  the  finishing  temperature  is  cone  06 
(1005°  C). 

Five  men  were  employed  at  the  time  of  visit,  in  September,  1926. 

Muresque  Tiles,  Inc.  Wm.  P.  Muir,  president  and  manager;  Chas. 
Orpin,  secretary;  1001  Twenty-second  Avenue,  Oakland.  This  is  a 
small  plant  for  making  hand-pressed  floor,  wall  and  mantel  tile,  and 
decorative  inserts.  Lincoln  and  lone  clays  are  used,  which  produce  a 
buff  or  cream  body.  Matt  glazes  are  used,  which  are  buffed  on  a 
wheel  after  firing,  producing  effects  similar  to  the  well-known 
Batchelder  tile,  made  in  Los  Angeles  (see  page  97).  An  oil-fired 
muffle  kiln  is  used.  No  further  details  would  be  furnished  by  the 
company. 

RemiJUird  Bn'cJi  Company.  C.  Remillard,  president;  R.  C.  Giroux, 
secretary.  Office,  332  Phelan  Building,  San  Francisco.  The  plant  is 
one  and  one-half  miles  northeast  of  Pleasanton,  on  the  main  line  of  the 
Southern  Pacific  Railroad.  The  plant  was  established  in  1889  and  has 
been  oi)erate(l  continuously  since  then.  Common  red  brick  are  manu- 
factured. 

The  clay  deposit  consists  of  a  sandy  loam,  25  feet  thick,  and  is  mined 
from  a  pit  one-(iuarter  mile  from  the  plant  by  a  drag-line  scra])er  oper- 
ated by  an  electric  hoist.  The  clay  is  loaded  into  cars  and  hauled  by 
motor  to  the  i)lant.  The  soft-mud  process  is  used.  The  brick  are  dried 
under  sheds  in  the  yard,  and  are  fired  in  two  16-compartment  Hoffman 
kilns,  of  20. 000  daily  capacity  each.  Fifty  men  are  employed  during 
the  season. 

Bibl:  Cal.  State  Min.  Bur.  Repts.  XII.  p.  381;  XIII.  p.  613;  Bull. 
38,  p.  242 ;  and  Prel.  Rept.  No.  7,  p.  37. 

Teclinkal  Porcelain  and  China  Ware  Company.  J.  Pagliero,  owner. 
Office  and  plant  420  Kains  Avenue,  Albany,  via  Berkeley.  This  is  a 
small  plant  manufacturing  porcelain  bath-room  fixtures  by  the  cast- 
ing process  from  a  mixture  of  California  clays.  One  square  up-draft 
kiln  is  used  for  both  biscuit  and  glost  firing.    Four  men  are  employed. 

Tesla:  The  coal  and  clay  deposits  of  Eocene  (Tejon)  age  in  Corral 
Hollow,  near  Telsa,  and  extending  for  a  short  distance  eastward  into 
San  Joaquin  County,  have  been  known  since  1862.  These  deposits 
have  been  worked  at  various  times  in  the  past,  notably  during  the 
])eriod  from  1897  to  1907.  The  coal  was  inferior  in  quality,  and  was 
costly  to  extract  on  account  of  steep  dij)  and  swelling  ground.  As  late  as 
1919  an  attempt  was  made  to  reopen  the  coal  mine,  at  which  time  the 
property  was  purchased  by  the  Beckman-Linden  Engineering  Corpora- 
tion of  San  Francisco,  and  considerable  sums  of  money  were  expended 
on  equipment  and  development  before  it  was  clearly  demonstrated  that 
commercial  success  could  not  be  expected  under  prevailing  conditions. 
The  principal  activities  in  the  past  have  centered  around  the  Tesla 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


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CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  45 

miue,  in  the  SE^  of  Sec.  26,  T.  3  S.,  R.  3  E.,  M.  D.  M.,  which  followed 
wliat  is  knoAvn  as  the  Eui-eka  coal  seam  1o  a  deptli  of  800  feet.  Some 
work  was  also  done  on  the  Summit  seam.  See  Plate  IV  for  a  surface 
map  of  the  district,  and  Plate  V  for  a  {geologic  cross-section.  In  develop- 
ing the  coal  deposits,  extensive  beds  of  clay  were  found.  The  clays 
were  of  various  grades,  ranging  from  liigli-gi-ade  i)lastic  fireclay  to 
red-burning  sewer  pipe  and  paving-brick  clays  and  shales.  Consid- 
erable quantities  of  high-grade  ({uartz  sand  were  also  discovered.  Two 
clay-working  plants  were  established  in  llie  district,  using  chiys  that 
were  obtained  from  the  coal  mine,  and  from  tunnels  and  open-cuts 
nearby.  The  Carnegie  Brick  and  Potterv  Companv  produced  sewer 
pipe  in  an  8-kiln  plant  in  the  Si  of  Sec.  30,  T.  3  S.,  II.  4  E.,  M.  I).  M., 
two  miles  east  of  Tesla,  and  also  had  a  45-kiln  plant  for  producing 
fire  brick,  face  brick,  and  terra  cotta  at  Carnegie,  four  miles  east  of 
Tesla.  These  operations  were  discontinued  in  1912,  some  years  after 
the  cessation  of  coal  mining  operation.s,  as  it  was  not  possible  to  obtain 
an  adeqnate  supi)ly  of  suitable  cla^'S  from  the  workings  near  the  surface 
after  the  coal  mine  was  abandoned. 

Tlie  district  must  still  be  considered  as  an  important  potential 
source  of  high-grade  fireclays,  as  there  seems  little  doubt  that  extensive 
prospecting  would  demonstrate  the  presence  of  many  millions  of  tons  of 
fireclay  that  would  be  equal,  if  not  better,  in  quality  to  any  refractory 
clays  now  being  mined  in  California.  There  is  little  justification  at 
I)resent,  however,  for  attempting  to  rejuvenate  clay  mining  in  the  dis- 
trict, as  the  fireclay  deposits  at  lone,  Amador  County,  and  at  Lincoln, 
Placer  County,  are  adequate  in  quality  and  quantity  for  present  needs, 
and  are  chea])ly  mined,  mainly  from  surface  workings,  whereas  under- 
ground mining  under  difficult  conditions  would  be  necessary  if  extensive 
operations  were  to  be  carried  on  at  Tesla. 

Ryan  Ranch  Deposit:  Owned  by  Wm.  Ryan,  Livermore.  In  1926 
and  1927  a  small  open  pit  (see  photo  No.  2)  was  excavated  on  an  out- 
crop of  fireclay  alongside  the  Livermore-Tesla  road  in  the  NW|  of  Sec. 
26,  T.  3  S.,  R.  3  E.,  M.  D.  ]\I.  The  workings  exposed  a  bed  of  white 
plastic  clay  6  to  8  feet  thick,  underlain  by  white  sandstone,  and  over- 
lain by  lignitic  shale.  The  strike  of  the  beds  is  nearly  east-west,  and 
the  dip  is  about  65°  north.  Sample  No.  259  was  taken,  and  the  test 
results  on  page  263  show  it  to  be  an  exceptionally  good  grade  of  fireclay, 
that  burns  nearly  white.  The  deposit  is  apparently  a  small  remnant 
of  Eocene  enclosed  in  Miocene  rocks,  and  there  is  little  evidence  of  the 
continuity  of  the  Eocene  at  this  point. 

Walrich  Pottery.  J.  A.  Wall,  owner,  1285  Hearst  Avenue,  Berkeley. 
Art  ware,  porcelain  specialties,  decorative  and  mantel  tile  are  made  at 
this  plant  from  a  white  semi-porcelain  body,  composed  of  Illinois  silica, 
California  (Campo)  feldspar,  English  china  and  English  ball  clay. 
Translucent  glazes  are  used,  in  a  wide  range  of  colors. 

]\Iost  of  the  shapes  are  east,  although  a  few  are  hand  pressed.  A 
Callfins  kiln,  20  in.  by  36  in.  by  20  in.,  heated  with  oil,  is  used  for  firing 
the  w^are.  The  biscuit  ware  is  fired  at  cone  4,  and  the  glost  firing  is  at 
cone  1. 

Westinghouse  Electric  and  Manufacturing  Company.  J.  W.  Ryan, 
manager ;  G.  ]\[.  Whisler,  assistant  manager ;  6121  Green  Street,  Emery- 


46 


DIVISION   OF    MINES   AND   MINING 


ville.  Til  is  is  a  branch  factory  of  tlie  parent  organization  of  Pennsyl- 
vania. 11  is  devoted  exclusively  to  the  manufacture  of  hio-li-voltage 
porcelain  iiisulatoi-s  and  is  the  ouly  ])lant  of  its  kind  in  California. 
The  raw  materials  used  are  Campo  (California)  feldspar,  Ottawa  (lUi- 


Photo  No.  2.     Ryan  Ranch  clay  deposit,  near  Te.sla, 
Alameda  County.     (Sample  No.  259.) 

nois)  flint,  Kentucky  ball  clay,  Georgia  china  clay,  lone  and  Lincoln 
(California)  sagger  clays. 

The  feldspar  and  flint  are  ground  in  a  ball  mill  for  two  hours  after 
which  thev  are  mixed  Avith  the  blunged  clays.  Prom  the  blunger  the 
slip  flows  'successively  through  an  agitator,  200  mesh  screens,  magnetic 
separator,  agitator  and  then  is  pumped  into  a  filter  press  where  the 


CLAY  RESOUHl  ES  ANT)  CERAMIC   IXDrSTKV 


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CLAY  RESOURCES  AXD  CERAIilir  INDUSTRY  49 

excess  Avater  is  removed.  The  filter  press  cakes  are  pugj^ed  and  then 
stored  in  concrete  cellars  for  about  three  weeks.  The  filter  press  room 
is  shown  on  ]>lioto  Xo.  '■^. 

Before  usin<r,  tlie  clay  is  ajrain  pujryed  to  the  best  size  for  the  insu- 
lator beinj?  made.  The  pup:s  of  clay  are  cut  to  correct  length  and 
.shaped  roiijrhly  by  hand  prior  to  placing-  in  the  pla.ster  of  paris  mold 
which  jiives  it  the  outer  shape.  Tlie  inside  shape  is  made  by  the  modern 
hot  press  method.  A  portion  of  tlie  hot  press  room  is  shown  on  piioto 
No.  4. 

From  the  hot  press,  the  mold  and  insulator  go  through  a  continuous- 
mold  release  di-yer  after  which  the  insulator  is  easily  removed  from  the 
mold.  The  next  operation  is  trimming  the  surface  next  to  the  mold 
to  include  tie  wire  grooves,  and  improve  the  surface  condition  of  the 
in.sulator. 

Trimming  is  followed  by  the  final  drying  in  a  tunnel-type  humidity 
dryer  wliich  operates  on  a  60-hour  scliedule.  After  drying,  an  Albany 
slip  glaze  is  applied  and  the  insulators  are  ready  for"  firing.  Special 
colors  can  also  be  supplied  for  indicating  phase,  voltage,  etc.  These 
are  white,  blue,  green,  chocolate,  black,  etc. 

For  firing  tiie  insulators  are  placed  in  saggers  which  in  turn  are 
placed  in  one  of  four  draft  kilns.  Each  kiln  is  16  feet  in  diameter  and 
12  feet  high  to  the  crown  and  the  average  burn  is  800,000  cubic  inches  of 
ware.  The  firing  is  done  with  gas  for  the  first  few  hours  after  which 
oil  is  u.sed  for  the  60  hr.  period.  The  temperature  is  controlled  bv 
means  of  recording  pyrometers  and  pyrometric  cones.  The  finishing 
temperature  is  cone  10  down  (approximately  1260  degrees  C).  The 
cooling  period  is  about  three  days. 

An  average  of  sixty-five  men  are  employed  in  this  plant. 

Woolenius  Tiles.  C.  A.  Elsenius,  OAvner  and  manager,  1631  Woolsey 
Street,  Berkeley.  This  is  a  small  plant  engaged  in  the  manufacture  of 
decorative  tile,  inserts,  and  mantel  pieces,  using  a  fireclav  bodv  made 
from  Lincoln  clay  (sample  Xo.  146,  p.  303)  and  Shepard^  (Tone)  sand 
(sample  Xo.  128,  p.  261).  The  clays  are  pulverized  to  50-mesh, 
pugged,  and  regular  shapes  are  made  in  a  tile  auger.  Special  designs 
are  hand  pre.s.sed.  A  thin  matt  glaze  is  fired  on  with  the  body,  ancl  is 
afterwards  partly  ivmoved  by  buffing  on  a  wheel.  A  rectangular 
down-draft  kiln,  heated  with  oil,  is  used  for  firing.  The  finishino- 
temperature  is  from  cone  5  to  cone  7.  " 

One  or  tAvo  men  are  employed  besides  the  owner. 

liibl   (Clay  Resources  of  Alameda  Countv)  :  State  Mineraloc'ist's 
Repts  X,  IX  91  ;  XTI,  p.  39  ;  Xin,  p.  5]  ;"  XIV,  p.  607.    Cal.  State 
Min.  Bur.  Bulletin  Xo.  38,  pp.  202,  204-206,  and  227  •  Prel  Rept 
Xo.  7,  i)p.  35-37,  94.     U.  S.  G.  S.  22d  Ann.  Rei)t.,  Pt    III    pp 
501-504.  '  '  ^^ 

AMADOR   COUNTY. 
General    Features. 

Amador  County  lies  to  the  east  of  the  Sacramento  Valley  and  extends 
from   the   lower   foothills   to   the   summit   of  the   Sierra  Nevada      It 
traverses  the  center  of  the  famous  I\Iother  Lode  gold  belt,  and  is  similar 
to  El  Dorado,  Calaveras,  Tuolumne  and  Mariposa  counties  in  climate 
physiography,  geology  and  natural  resources.     Amador  is  the  smallest 

4 — 54979 


50  DIVISION   OF    MINES   AND   MINING 

county  of  the  group,  and  contains  6U1  .s(j[uai-e  miles.  Tiie  population 
is  about  SOOO.  Ciold  and  clay  mining  and  stock  raising  are  the  prin- 
cipal industries.  Tlie  county  is  well  ])rovided  with  good  roads,  con- 
necting the  princii)al  towns  with  each  other,  and  with  the  Sacramento 
Valley.  A  branch  of  the  Southern  Pacific  Railroad  extends  from  Gait 
to  lone,  where  it  connects  with  tlie  Amador  Central,  running  to  Martel 
and  serving  the  gold  mines  in  the  vicinity  of  Jackson  and  Sutter  Creek, 
the  principal  towns  in  the  county.  There  is  timber  suitable  for  under- 
ground mining  in  the  mountains.  Electric  power  is  supplied  to  most 
of  the  towns  in  the  county  by  the  Pacific  Gas  and  Electric  Compau}-, 
and  water  is  supplied  by  this  company  to  the  Mother  Lode  section  of 
the  county. 

The  geology  and  mineral  resources  of  tlie  county  have  recently  been 
summarized  by  Logan  •? 

"White  clay  forms  a  conspicuous  part  of  tlie  lone  (Tertiary)  beds,  which  extend 
across  the  entire  west  side  of  the  county  from  north  to  south.  This  and  other 
colored  clays  nearby  form  the  basis  of  an  important  industry,  supplying  potteries 
in  various  parts  of  the  state. 

"Also  associated  with  the  lone  beds  and  usually  within  100  feet  or  less  of  the 
surface,  near  Carbondale,  lone,  Buena  Vista  and  Lancha  Plana,  occur  numerous 
deposits  of  brown  lignite.    This  was  mined  at  several  places  until  a  few  years  ago.     .     .     . 

"Farther  east,  alternating  beds  of  Mariposa  (Jurassic)  black  slate,  amphibolite 
schist,  serpentine  and  Calaveras  (Carboniferous)  rocks  extend  northwest,  parallel 
to  the  axis  of  the  mountain  range  of  which  they  form  the  Hank.  In  the  amiptibolite 
schist  numerous  copper  mines  and  prospects  occur,  but  are  all  idle  now.  Ohromite 
occurs  in  the  serpentine,  and  many  small  lenses  of  limestone  in  the  Carboniferous 
rocks.  These  formations  begin  about  a  mile  east  of  lone  and  extend  for  seven 
miles  eastward,  where  the  Mother  Lode  mines  occur,  in  another  belt  of  black 
Mariposa  slate.  This  slate  enters  the  county  at  Middle  Bar  bridge  on  Mokelumne 
River,  running  thence  northwest  tlirough  and  beyond  the  county.  Vk^ith  an  average 
width  of  about  one-half  mile,  and  in  many  of  the  mine  workings  narrowing  "to  only 
a  few  hundred  feet,  this  slate  belt  and  the  immediatel.y  adjoining  and  at  times 
intercalated  areas  of  altered  igneous  rocks  contain  all  the  important  gold  quartz 
mines  of   the   county. 

"To  the  east  of  the  Mother  Lode  the  rocks  are  nearly  all  of  Carboniferous  age  for 
a  distance  of  ten  miles,  until  an  elevation  of  al^out  3000  feet  is  reached,  where  the 
granodiorite  forming  the  core  of  the  mountains  appears.  At  Oleta  in  the  northern 
part  of  the  county  and  at  Volcano  much  placer  gold  has  been  produced.  A  series 
of  detached  gravel  bodies  covered  by  rhyolite  and  andesite  extends  across  the  county 
between  these  two  old  camps.  The  gravel  in  this  region  represents  remnants  of  Tertiary 
river  deposits.  In  the  western  part  of  the  county,  near  lone,  are  accumulations  of 
delta  and  shore  gravel,  deposited  when  the  inland  sea  or  gulf  had  its  shores  in  that 
vicinity,  during  the  time  of  the  lone  disposition,  which  was  at  the  same  time  as  the 
formation  of  prevolcanic  channels  m  the  rivers  of  the  Sierra  Nevada.  In  places 
where  it  has  been  reconcentrated  by  later  streams  some  of  it  has  been  rich  enough 
to  mine  profitably.  There  are  also  beds  of  white  and  red  sandstone  in  the  lone 
formations,  which  have  been  worked  in  the  past.  Marble  occurs  two  miles  east  of 
Plymouth  and  eight  miles  east  of  Sutter  Creek,  enclosed  in  the  Calaveras  formation. 
Besides  the  numerous  small  bodies  of  limestone,  ther#  are  two  especially  large  areas, 
one  at  Volcano  and  one  four  miles  northwest  of  that  town.  Asbestos,  talc,  ocher 
and  low-grade  iron  ores  also  occur." 

Clay   Resources." 

The  lone-Carbondale  district  is  noted  for  its  high-grade  fire  clays  and 
fire  sands.  Associated  with  the  high-grade  clays  and  sands  are  a 
number  of  important  red-burning  plastic  clays.  A  fire  brick  plant  has 
been  in  operation  near  lone  for  many  years.  An  experimental  clay 
washing  plant  was  operated  a  number  of  years  ago  on  the  N.  Clark 
and  Sons  property  near  Carbondale  (see  Plate  VI),  and  another  wash- 
ing plant  was  operated  near  lone  by  the  Philadelphia  Quartz  Company. 
Both  of  these  operations  were  abandoned  prior  to  1921,  but  in  Febru- 
ary, 1927,  a  new  plant  was  erected  on  the  Carlile  property  by  E.  E. 
Tremain,  lessee. 


^  Logan,  C.  A.,  Amador  County;  State  Mineralogist's  Report  XXIII,  p.  132,  April, 
1927. 

-  The  report  by  Logan,  op.  cit.,  was  freely  drawn  upon  in  the  preparation  of  this 
summary. 


rT.4V  RVSOTTRPFS    AVH   PF.RAAfTr    TNDT'STRY 


51 


50  DIVISION   OF    MIXES   AND   MINING 

county  of  the  group,  and  contains  601  square  miles.  The  population 
is  about  8000.  Gold  and  clay  mining  and  stock  raising  are  the  prin- 
cipal industries.  The  county  is  well  j)rovided  with  good  roads,  con- 
necting the  principal  towns  with  each  other,  and  with  the  ISacraniento 
Valley.  A  branch  of  the  Southern  Pacific  Railroad  extends  from  Gait 
to  lone,  where  it  connects  with  tlie  Amador  Central,  running  to  Martel 
and  serving  the  gold  mines  in  the  vicinity  of  Jackson  and  Sutter  Creek, 
the  principal  towns  in  the  county.  There  is  timber  suitable  for  under- 
ground mining  in  the  mountains.  Electric  power  is  supplied  to  most 
of  the  towns  in  the  county  by  the  Pacific  Gas  and  Electric  Company, 
and  water  is  supplied  by  this  company  to  the  Mother  Lode  section  of 
the  county. 

The  geology  and  mineral  resources  of  the  county  have  recently  been 
summarized  by  Logan  :^ 

"White  clay  forms  a  conspicuous  part  of  the  lone  (Tertiary)  beds,  which  extend 
across  tlie  entire  west  side  of  the  county  from  nortli  lo  south.  This  and  other 
colored  clays  nearby  form  the  basis  of  an  important  industry,  supplying  potteries 
in  various  parts  of  the  state. 

"Also  associated  with  the  lone  beds  and  usually  within  100  feet  or  less  of  the 
surface,  near  Carbondale,  lone,  Buena  "Vista  and  Lancha  Plana,  occur  numerous 
deposits  of  brown  lignite.    This  was  mined  at  several  places  until  a  few  years  ago.     .     .     . 

"Farther  east,  alternating  beds  of  Mariposa  (Jurassic)  black  slate,  amphibolite 
schist,  serpentine  and  Calaveras  (Carboniferous)  rocks  extend  northwest,  parallel 
to  the  axis  of  the  mountain  range  of  which  they  form  the  flank.  In  the  amiphbolite 
schist  numerous  copper  mines  and  prospects  occur,  but  are  all  idle  now.  Chromite 
occurs  in  the  serpentine,  and  many  small  lenses  of  limestone  in  the  Carboniferous 
rocks.  These  formations  begin  about  a  mile  east  of  lone  and  extend  for  seven 
miles  eastward,  where  the  Mother  Lode  mines  occur,  in  another  belt  of  black 
Mariposa  slate.  This  slate  enters  the  county  at  Middle  Bar  bridge  on  Mokelumne 
River,  running  thence  northwest  through  and  beyond  the  county.  W'ith  an  average 
width  of  about  one-half  mile,  and  in  many  of  the  mine  workings  narrowing -to  only 
a  few  hundred  feet,  this  slate  belt  and  the  immediately  adjoining  and  at  times 
intercalated  areas  of  altered  igneous  rocks  contain  all  the  important  gold  quartz 
mines  of   the   county. 

"To  the  east  of  the  Mother  Lode  the  rocks  are  nearly  all  of  Carboniferous  age  for 
a  distance  of  ten  miles,  until  an  elevation  of  about  3000  feet  is  reached,  w-here  the 
granodiorite  forming  the  core  of  the  mountains  appears.  At  Oleta  in  the  northern 
part  of  the  county  and  at  Volcano  much  placer  gold  has  been  produced.  A  series 
of  detached  gravel  bodies  covered  by  rhyolite  and  andesite  extends  across  the  county 
between  these  two  old  camps.  The  gravel  in  this  region  represents  remnants  of  Tertiary 
river  deposits.  In  the  western  part  of  the  county,  near  lone,  are  accumulations  of 
delta  and  shore  gravel,  deposited  when  the  inland  sea  or  gulf  had  its  shores  in  that 
vicinity,  during  the  time  of  the  lone  disposition,  which  was  at  the  same  time  as  the 
formation  of  prevolcanic  channels  m  the  rivers  of  the  Sierra  Nevada.  In  places 
where  it  has  been  reconcentrated  by  later  streams  some  of  it  has  been  rich  enough 
to  mine  profitably.  There  are  also  beds  of  white  and  red  sandstone  in  the  lone 
formations,  which  have  been  worked  in  the  past.  Marble  occurs  two  miles  east  of 
Plymouth  and  eight  miles  east  of  Sutter  Creek,  enclosed  in  the  Calaveras  formation. 
Besides  the  numerous  small  bodies  of  limestone,  therdT  are  two  especially  large  areas, 
one  at  Volcano  and  one  four  miles  northwest  of  that  town.  Asbestos,  talc,  ocher 
and  low-grade  iron  ores  also  occur." 

Clay   Resources.- 

The  lone-Carbondale  district  is  noted  for  its  high-grade  fire  clays  and 
fire  sands.  Associated  with  the  high-grade  clays  and  sands  are  a 
number  of  important  red-burning  plastic  clays.  A  fire  brick  plant  has 
been  in  operation  near  lone  for  many  years.  An  experimental  clay 
washing  plant  was  operated  a  number  of  years  ago  on  the  N.  Clark 
and  Sons  property  near  Carbondale  (see  Plate  VI),  and  another  wash- 
ing plant  was  operated  near  lone  by  the  Philadelphia  Quartz  Company. 
Both  of  these  operations  w^ere  abandoned  prior  to  1921,  but  in  Febru- 
ary, 1927,  a  new  plant  was  erected  on  the  Carlile  property  by  E.  E. 
Tremain,  lessee. 


1  Logan,  C.  A.,  Amador  County;  State  Mineralogist's  Report  XXIII,  p.  132,  April, 
1927. 

=  The  report  by  Logan,  op.  cit.,  was  freely  drawn  upon  in  the  preparation  of  this 
summary. 


MAP    0'=~ 

/ONE  D/5TR/CT 

AMADOR  COUNTY,  JZALJ/T 
S/-/C\V/AiO    BOUNDA/RIES 

or 
ARROYO    SECO  GRANT. 

CLAY  DEPOS/rS 


T6N 
|T5N 


Plate  VI.     PioiJerly  map  of  lone   district.      (By   courtesy   ot   S.    E.    Kieffcr. ) 


[14'JT9 — lacing  page  50 


50 


DIVISION   OF   MINES  AND   MINING 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  51 

Enougli  int'onnatioii  lias  been  obtained  from  those  various  wasliing 
operations  to  doinonstrate  the  fact  that  it  is  possihh'  to  prodneo  a  quartz 
sand  suitable  for  tlie  inanufaeture  of  <ilass  and  sodium  silicate,  and  for 
use  as  "flint"  in  porcelain  bodies.  The  kaolin  content  of  the  sands 
is  seldom  in  excess  of  25^>,  and  "reuerally  contains  enough  iron  oxide  to 
cause  it  to  fire  to  a  lifrht-ci-i'am  coloi-,  althoujih  in  ])laces  it  is  sufficiently 
pure  to  tire  to  a  satisfactory  white  coioi'  for  use  in  white-ware  bodies. 
Several  factors  adversely  affect  the  establishment  of  a  financially-sound 
washing  operation  in  the  district,  among  which  may  be  mentioned  the 
c()m])aratively  high  freight  rate  to  i)roducing  centers,  the  low  cost  of 
IJelgiau  saiul,  which  is  delivered  to  California  jjorts  at  a  price  of 
about  $5  per  ton,  the  low  content  of  high-grade  kaolin  in  most  of  the 
sands,  and  the  fact  that  few  important  plants  now  using  English  or 
Florida  kaolin  would  be  willing  to  change  to  the  use  of  local  material 
unless  as.sured  of  aji  ample  supply  of  uniformly  high-grade  kaolin  over 
a  long  period  of  years. 

A  new  use  for  lone  sand  is  in  making  white  cement.  One  large 
company  has  recently  bought  a  sand  property,  and  it  is  anticipated  that 
others  will  follow. 

The  clays  occur  as  a  part  of  the  lone  formation  and  are  distributed 
over  a  length  of  12  miles  and  a  wadth  of  4^  miles  in  the  county,  with 
extensions  into  Sacramento  County  on  the  northwest  and  into  Cala- 
veras County  on  the  southeast.  In  most  places  the  clays  are  covered 
by  an  overburden  of  soil,  sand,  tuff,  volcanic  breccia,  and  sandstone, 
varying  from  a  few  inches  to  a  maximum  of  20  feet  over  most  of  the 
depo.sits  now  being  worked.  The  clay  beds  have  a  slight  westerly  dip. 
Lignite  coal,  interbedded  with  clay,  is  found  at  depths  of  40  to  125  feet. 
The  clay  beds  are  not  continuous,  and  the  extreme  limits  of  the  i)robable 
boundaries  of  the  deposits  have  not  been  determined,  but  enough  mining 
and  drill  prospecting  has  been  done  to  demonstrate  the  fact  that  there 
is  an  ample  supply  of  clay  for  many  years. 

The  contemporary  theory  of  the  origin  of  the  clays  has  been  well 
summarized  by  Logan. ^ 

"The  white  clay  apparently  came  from  the  rhyolite  ash  flow.s,  which  have  been 
found  directly  over  the  older  series  of  gold-bearing  gravel  channel.s  in  the  Sierra 
Nevada.  Probably  a  long  enough  i)eriod  of  erosion  ensued  after  these  initial  ash 
outljursts  to  ])ermit  the  carrying  of  the  finer  sized  and  lighter  particles  down  the 
streams  into  the  shore  waters  of  the  inland  sea  which  then  filled  the  Sacramento  and 
San  .Toaquin  vallejs.  P.efore  the  white  ash  was  covered  and  jircserved  by  later  flows 
of  darker  colored  lireccia  and  ash,  a   large  i)art   of  it   was  thus  swept  away. 

"That  the  clay  is  of  rhyolitic  origin,  possibly  mixed  with  the  quartz  sand  from 
those  mysterious  earlier  rivers  whose  remaining  sections  now  show  such  a  remarkalile 
amount  of  quartz  cobbles,  with  scarcely  any  other  rock,  is  substantiated  by  the 
analyses.  The  sandy  clay  carries  about  70%  silica,  20%  alumina.  1.25%  iron  oxides, 
0.3%  CaO,  and  0.2%  MgO.  Other  samples  where  the  p<»rcentage  of  silica  is  less, 
contain  32%  to  34%  dry  weight  of  alumina.  The  amount  of  calcium  is  typically 
low  and  it  is  erratically  distributed,  sometime.s  as  gypsum  seams.  As  the  percentage 
of  iron  increases  the  clay  becomes  mottled  red  and  yellow,  but  the  usual  color  is 
white,  cream  or  light  lilue." 

Arroyo  Seco  Grant. 

Introduction. 

The  greater  part  of  the  lone  clay  deposits  lie  within  the  boundaries 
of  the  Rancho  Arroyo  Seco,  which  was  formerly  owned  by  the  McKis- 
sick  Cattle  Company,  who  leased  many  of  the  clay  deposits  to  Bacon 
&  Bacon  (see  post)  and  other  operators  in  the  district.  In  1926  the 
grant  was  purchased  by  S.  E.  Kieffer,  57  Post  Street,  San  Francisco, 

'  Op.  cit.,  p.   135. 


52 


DIVISION  OF   MINES  AND  MINING 


who  then  leased  the  clay  j^roperties  to  G.  A.  Starkweather.  ]\Ir.  Stark- 
weather is  operating  some  of  the  properties,  but  has  subleased  a  num- 
ber of  them  to  various  ojierators.  A  map  of  tlie  prant,  and  of  the 
surrounding  pro])erty,  sliowiufj-  the  location  of  tlie  i)rincipal  clay 
deposits,  is  sliown  on  plate  VI. 

Core  Drilling. 

Durin<r  the  seasons  of  192o  and  1926,  a  larpre  amount  of  core  drilling 
Avas  done  in  the  lone  district  under  the  direction  of  ]\Ir.  S.  E.  KiefFer, 
consulting  engineer.  Many  of  these  holes  penetrated  the  sand,  clay  and 
coal  beds  to  depths  of  150  feet  or  more.  Through  the  courtesy  of  ^Ir. 
KiefPer,  a  number  of  core-drill  clay  samples  were  obtained  for  testing. 
The  location  of  the  holes  from  which  these  samples  were  taken  is 
shown  on  the  map,  plate  VI,  and  the  approximate  depth  of  the  samples 
from  the  surface,  as  well  as  the  approximate  thickness  of  each  forma- 
tion, are  given  in  table  No.  8. 


TABLE   NO.  8. 

Descr 

ption  of  Core  Drill  Samples  from 

lone  District. 

Depth 

of  top 

• 

of  .sample 

Sample 

Drill 

Location 

from           Thickness 

General 

No. 

hole  No. 

of  hole 

surface,       of  forma- 

character  of 

239 

XE.  cor 

feet           tion.  feet 

material 

Lot   254 

37                   25 

Fire  sand 

240 

E.  side 

Lot   237 

100(?) 

Plastic  firclay 

243 

47 

Lot   336 

230                   16 

Sandy  clay,  poor  quality 

244 

54 

Lot   324 

13                   19 

Plastic  fireclay 

245 

55-  1 

Lot   237 

32                   41 

Plastic  fireclay 

247 

55-  2 

Lot   237 

73                    18 

Plastic  fireclay 

246 

55-  3 

Lot   237 

93                   16 

Plastic  fireclay 

248 

56-  1 

Lot   237 

4                   24 

Plastic  fireclay 

249 

56-  2 

Lot   237 

44                   36 

Plastic  fireclay 

250 

56-  3 

Lot   237 

80                   30 

Plastic  fireclay 

251 

57-  1 

Lot   237 

3                     9 

Plastic  red-burning 

252 

57-  2 

Lot   237 

12                   10 

Plastic  fireclay 

253 

57-  3 

Lot   237 

22                   20 

PL  fireclay,  nearly  white 

254 

57-  4 

Lot   237 

42                   26 

Buff   plastic   fireclay 

255 

57-  5 

Lot   237 

68                   46 

Red  plastic,  cone  26 

256 

60 

Lot  255 

(near                — 
hottom) 

Red  plastic,  cone  19-20 

257 

62 

Lot   255 

66                     6 

PI.  fireclay,  nearly  white 

258 

61 

Lot   255 

75(?)             10(?) 

Buff  plastic  fireclay 

It  is  not  po.ssible  from  the  data  available  to  establish  continuity  of 
the  various  beds  of  clay  and  sand  represented  by  the  core  drill  samples, 
but  the  presence  of  large  reserves  of  high-grade  clays  is  well  demon- 
strated, Mo.st  of  these  clays,  however,  can  not  be  mined  under  present 
conditions  while  large  deposits  of  good  material  are  still  available  for 
open-pit  mining. 

Active    Deposits. 

Gage  Pit.  The  Gage  pit,  leased  and  operated  by  G.  A.  Starkweather, 
is  in  Lot  224  of  the  Arroyo  Seco  grant,  two  miles  east  of  Lignite  siding 
on  the  Southern  Pacific  Railroad  northeast  of  lone.  The  clay  is 
dazzling  white  in  color,  slightly  plastic,  and  has  a  talcy  feel.  It  has 
been  used  by  the  West  Coast  Calcimine  Co.  The  pit  at  the  time  of 
visit,  in  August,  1925,  was  100  feet  wide  at  the  face,  which  had 
advanced  120  feet  from  the  approach.  The  exposed  clay  bank  was  12 
feet  thick.     ^Mr.  Bacon  stated  that  the  total  average  thickness  of  this 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  53 

clay  is  16  feet.    The  clay  is  capped  by  less  than  three  feet  of  volcanic 
breccia. 

A  view  of  tills  pit,  looking?  eastward,  is  shown  on  pholo  No.  '). 
ISample  Xo.  120  was  taken  for  test,  the  results  of  which  are  given  on 
page  273.  Tlic  usiuil  annual  i)roduction  is  600  tons,  all  iiiined  and 
loaded  by  hand  and  hauled  in  auto  trucks  to  Lignite. 

Jones  Butte  Deposit.  The  Jones  Butte  clay  mine,  sub-leased  from 
Mr.  Starkweather  and  operated  by  the  Stockton  Fire  Brick  Co.,  is  in 
Lot  240  of  the  Arroyo  Seco  grant,  on  the  western  slope  of  Jones  Butte, 
also  known  to  local  iniuibitants  as  Deutschke  Hill.  The  mine  is  1.5 
miles  by  road  fi-om  Edgar  siding,  on  the  Southern  Pacific  Railroad, 
two  miles  northwest  from  lone. 

A  geological  study  of  the  deposit  was  made  by  C.  X.  Scluiette,  at 
one  time  in  the  employ  of  the  Stockton  com])any  as  a  geologist  and 


Photo  No.  5.     Gage  clay  pit,  near  Lignite,  looking  eastward.     (Sample  No.  125.) 

engineer.  The  successive  formations,  from  the  top  of  the  hill  down- 
ward, are  lava,  tuff,  gravel,  clay,  and  lateritic  iron.  The  clay  bed  is  lens 
shaped  in  the  north-south  section  of  the  hill,  and  wedge  shaped  in  the 
east-west  section,  thinning  toward  the  east.  The  cldy  in  the  mining 
area  covered  by  o])erations  in  August,  1925,  was  8  to  10  feet  thick  and 
there  was  an  additional  2-foot  bed  of  extremely  'fat'  or  'unctuous'  clay 
in  the  roof.  The  floor  has  a  general  pitch  toward  the  south,  and  min- 
ing is  complicated  by  the  presence  of  .sharp  rolls  in  the  floor  in  places. 
The  floor  is  generally  red  lateritic  iron,  but  in  idaces  this  is  covered 
by  a  variable  thickness  of  yellow  plastic  clay. 

The  mine  is  worked  entirely  by  underground  methods.  The  general 
plan,  modified  by  local  irregularities,  is  to  run  drifts  in  a  general 
easterly  direction  on  a  slightly  ascending  grade  on  approximately 
20-foot  centers.  The  drifts  are  as  .small  as  is  consistent  with  efficient 
driving  and  tramming,  usually  five  by  seven  feet.  Upon  reaching  the 
limit  of  the  block  to  be  mined,  or  the  limit  of  workable  thickness,  the 
retreat  is  made  by  slabbing  to  the  roof  and  slicing  a  five  cut  from  each 


54 


DIVISION   OF    MINES   AND   MINING 


side  of  the  drift,  leaving  a  pillar  approximately  5  feet  in  width  to  sup- 
port the  rooms  while  the  retreat  is  in  progress.  The  minimum  extrac- 
tion of  clay  in  the  minable  area  is  thus  75%  of  the  total.  Where  the 
roof  is  strong  enough,  the  extraction  can  be  increased  by  further  pillar 
robbing. 

At  the  working  faces,  mine  cars  are  loaded  by  hand  shoveling,  and 
are  trammed  by  hand  for  a  minimum  distance  of  400  feet  to  a  bin  near 
the  portal  of  the  tunnel.  From  here  the  clay  is  drawn  off  into  an  auto 
truck  for  transportation  to  the  car-loading  bin  at  Edgar. 

The  mine  is  normally  operated  on  a  production  schedule  of  four  cars 
(total  200  tons)  per  week  for  a  period  of  four  months,  or  somewhat 
in  excess  of  3000  tons  of  clay  per  year.  The  number  of  men  employed, 
including  a  foreman  and  a  truck  driver,  is  five. 

Three  samples  were  taken.  No.  120  is  the  main  'Edwin'  clay.  The 
test  results,  page  272,  indicate  that  it  is  one  of  the  best  pla.stic  fire- 


Photo  No.  G.      Jones  Butte  Mine.  Arroyo  Seco  Raiicho,  facing  eastward  toward 
portal  of  tunnel.      (Samples  No.  120,  121  and  122.) 


clays  in  California,  but  shows  the  high  shrinkage  and  fire  cracking 
typical  of  the  lone  clays.  Sample  No.  121  is  the  '  unctuous '  clay  occur- 
ring in  the  roof  of  the  mine.  It  was  taken,  and  the  test  work  done  (see 
page  302),  as  a  matter  of  general  interest,  altliough  the  known  thick- 
ness of  the  bed  is  insufficient  for  commercial  i)roduetioii.  Sample  No. 
122  is  the  '  Laterite, '  which  has  no  present  commercial  value,  but  is  con- 
sidered of  sufficient  interest  to  warrant  a  record  of  its  properties,  which 
is  given  on  ]iage  328. 

A  view  of  the  propciiy  near  the  jiortal  of  tlie  tunnel  is  sliown  on 
photo  No.  (j. 

Shepard  Pit    (lea.sed  by  G.  A.   Starkweather).     The  Shepard  sand 
pit  is  f  mile  from  lone  at  Shepard  spur  on  the  Amador  Central  Rail- 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


55 


i-oad.  The  easteru  boundary  of  the  property  adjoins  the  Avostern 
boundary  of  the  Newman  sand  pit.  A  vieAV  of  tlie  pit  is  shown  on  photo 
No.  8,  from  Avhich  the  extent  of  open  pit  mining  and  the  present  method 
of  underground  mining  by  pillar  and  room  can  be  seen.  The  sand 
has  an  avn-aut'  tliickupss  of  Ki  feci.     The  capping  of  volcanic  breccia 


Photo  No.  7.     Barber  ur  Sliei)ard  .sand  pit  one  mile  east  of  lone. 


Photo  No.  8.     Sand  pit  subleased  by  U\o  lone  Fire  Brick  Co.     (Sample  No.  140.) 

is  sufficiently  strong  so  that  rooms  can  be  driven  into  the  deposit 
nearly  to  the  full  height  of  the  sand  bed,  and  wide  enough  to  permit 
the  entrance  of  auto  trucks  to  the  loading  face.  Round  pillars  of  sand 
are  left  at  api)roximately  25  foot  intersections,  to  support  the  back. 
The  sand  has  been  mined  in  this  fashion  over  a  considerable  area.  See 
])hoto  No.  7. 


56 


DIVISION   OF    MINES   AND   MINING 


Sample  No.  128  was  taken  for  test,  the  results  of  which  are  given  on 
])aij'e  261.  The  sand  is  fine  grained,  nearly  wliite,  and  contains  enougli 
clay  to  develop  slight  i)lasticity  and  bonding  power.  It  is  widely 
used  by  fire  brick  and  terra  cotta  manufacturers  as  a  fine  grog.  The 
normal  output  from  the  Shepard  pit  is  15,000  tons  per  year.  At  the 
present  rate  of  mining,  the  reserve  of  sand  in  sight  is  sufficient  for  manj' 
years,  although  mining  costs  will  be  higher  as  mining  proceeds  fartlier 
from  the  openings  into  the  rooms. 

Photo  No.  8  shows  a  nearby  sand  pit,  subleased  by  the  I  one  Fire 
Brick  Co.,  from  which  sample  No.  140  was  taken.     See  page  280. 

Yam  Deposit.  The  Yarn  clay  pit,  leased  and  operated  by  G.  A. 
Starkweather,  is  located  on  lot  232  of  the  Arroyo  Seco  grant,  100  yards 
north  of  a  siding  at  Lignite  on  the  Southern  Pacific  Railroad,  four 
miles  northwest  of  lone. 

Photo  No.  9  is  a  view  of  this  ]nt.     The  overburden  is  less  than  three 


Photo  No.  9.      Yaru  clay  pit,  lone.      (Samples  No.   123,  124.) 

feet  in  thickness.  The  upper  bed  (sample  No.  123,  p.  335),  clearly  shown 
in  the  photograph,  is  designated  Yaru  No.  2.  It  is  a  yellowish  and 
blue-gray  plastic  fire  clay  6  feet  thick.  The  lower  bed  (sample  No. 
124,  p.  302),  is  known  as  Yaru  No.  1,  and  is  somewhat  lighter  in  color, 
but  contains  yellowi.sh  streaks  along  fracture  planes,  and  occasional 
nodules  of  iron-stained  sand.  A  car  hoist  is  used  to  elevate  the  clay 
from  the  bottom  of  the  pit  to  a  hot)per  on  the  surface  where  it  is  dumped 
into  a  truck  for  the  short  haul  to  the  railroad  siding.  The  thickness 
of  Yaru  No.  1  exposed  by  mining  operations  is  25  to  30  feet.  Borings 
in  this  clay  are  said  to  indicate  a  total  thickness  of  90  feet,  but 
streaks  of  sand  are  encountered  in  places. 

Total  shipments  of  Yaru  No.  1  and  No.  2  are  normally  4000  tons  per 
year. 

Miscellaneous  Operations. 

Bacon   cf'   Bacon.    Mark    J.    Bacon,    manager,    lone.      This    firm    is 
engaged  in  a  general  clay-mining  business,  working  some  properties  for 


CLAY  RESOURCES  AND  (■KRA:\Iir  INDITSTRY  57 

the  owin'1-s  under  contract  and  also  sliipping  to  numerous  consumers 
from  pits  which  they  own  oi-  K-ase.  Twenty-five  men,  two  steam 
shovels  and  six  ti-ucks  arc  employed  during  the  operating  season  from 
early  in  A{)ril  to  the  end  of  the  dry  season. 

Two  of  the  properties  owned  by  Bacon  and  Bacon  are  here  described, 
the  Bacon  Ked  (Lane  mottled)  and  the  Chocolate  i)its. 

Bacon  Red:  This  is  on  an  80-acre  tract,  comprising  the  NW}  of 
Sec.  32,  T.  6  N.,  R.  10  E.,  M.  D.  M.,  near  the  intersection  of  the  Jack- 
son highway  and  the  Amador  Central  Railroad,  1.8  miles  southeast  of 
lone.  The  clay  is  a  fine-grained  plastic,  red-wliite  mottled  clay  (sample 
No.  127,  ]).  335).  and  is  quite  characteristic  of  the  region.  It  is  mined 
from  an  oi)en  ])it,  150  feet  long  at  the  face.  In  1925  the  pit  had 
advanced  60  feet  in  from  the  starting  ])oint,  and  the  exposed  clay  baidv 
was  15  feet  high,  covered  by  shallow  overl)urden  of  loose  gravel.  The 
overburden  will  gradually  increase  as  the  clay  is  followed  into  the 
hill,  but  the  maximum  thickness  of  overburden  will  probably  not  be 
excessive,  as  the  hill  is  low,  and  has  a  gentle  slope.  The  clay  is  evi- 
dently not  bottomed  by  the  floor  of  the  i)it,  and  it  is  stated  that  the 
total  thickness  of  clay,  as  determined  by  boring,  is  nearly  40  feet. 

The  normal  production  from  this  pit  is  1000  tons  per  year,  all  mined 
by  hand.  There  is  no  siding  at  the  ])it,  the  clay  being  hauled  in  trucks 
to  one  of  the  loading  platforms  maintained  by  Mv.  Bacon. 

Chocolate  Pit  :  The  chocolate  pit  is  3  miles  north  of  Carbondale. 
Two  varieties  of  clay  are  mined  from  this  pit.  The  upper  bed,  4  to  5 
feet  thick,  is  a  chocolate-colored  plastic  clay  (sample  No.  137,  p.  266) 
of  special  value  in  the  manufacture  of  saggers.  This  is  underlain  by 
Ihe  Bacon  bottom  (sample  No.  l-'}8,  p.  280),  a  4—5  foot  bed  of  white- 
burning  i)lastic  clay  occasionally  used  in  sanitary  ware  bodies.  The 
overburden  is  less  than  four  feet  thick,  so  that  these  clays  can  readily 
be  quarried. 

The  ])roduction  from  this  ])it  has  been  small,  mainly  on  account  of 
the  length  of  haul  compared  to  other  varieties  that  have  nearly  the 
same  properties.  About  500  tons  of  chocolate  and  100  tons  of  Bacon 
bottom  are  mined  each  year.  The  ]iit  was  150  ft.  long,  and  40  ft. 
wide  at  the  time  of  the  visit  in  July,  1925. 

CarJile  Claij  and  Sand  Dcpusit.^  Mrs.  Sarah  E.  Carlile,  lone,  owner; 
E.  E.  Tremain,  Buena  Vista,  via  R.  F.  D.,  lone,  lessee.  The  propertv 
contains  60  acres  on  W|  NW]  Sec.  8,  T.  5  N.,  R.  10  E.,  M.  D.  M.,  four 
miles  from  lone  and  2.8  miles  bj^  road  to  the  nearest  railroad  spur. 
The  property  was  not  worked  prior  to  1927. 

In  February,  1927,  a  plant  was  being  erected  to  wash  the  sand  and 
clay.  A  bed  of  wdiite  sandy  clay,  overlain  by  two  to  seven  feet  of 
brown  clay,  had  been  stripped  over  an  area  about  80  feet  square. 
According  to  present  i)lans,  the  clay  will  be  dug  by  drag-line  sci-aper. 
The  washing  and  settling  plant  comprises  several  hundred  feet  of 
sluices  with  sand  traps  and  eight  large  clay-settling  tanks.  The  sand  is 
expected  to  settle  out  on  the  way  through  the  sluices  and  traps,  leaving 
the  clay  in  suspension,  free  from  grit,  to  pass  to  the  settling  tanks, 
from  which  it  will  be  drawn,  after  which  it  will  be  filtered  and  dried. 

'Entire  description  by  C  A.  Logan,  op.  cit..  ji.  130,  who  visiterl  the  i)roi)erl\-  in 
1927,  after  construction  work  had  been  started. 


58  DIVISION   OF    MINES  AND   MINING 

The  estimated  capacity  is  10  tons  a  day.      The  sand  is  not  at  i)resent 
being  considered  for  marlvcting. 

The  author  visited  the  property  in  1926  before  construction  work  had 
been  started,  and  took  a  sample.  No.  208,  from  a  shallow  open  pit.  The 
test  results  are  on  page  262. 

N.  Clark  and  Sons  (see  under  Alameda  County)  own  two  important 
pits  in  the  lone  district,  tlie  Clark  sand  pit  and  the  Doscli  clay  pit. 

Clark  Sand  Pit  :  The  Clark  sand  pit,  owned  by  N.  Clark  and  Sons 
of  San  Francisco  and  Alameda,  is  an  HO-acre  property  in  the  SW| 
of  Sec.  28,  T.  7  N.,  R.  9  E.,  1.8  miles  by  road  northeast  of  Carbondale. 
and  0.8  miles  northeast  of  the  Harvey  claj'  pit.  The  sand  bed  is  25 
to  40  feet  thick,  and  is  overlain  by  a  variable  thickness  of  volcanic 
breccia.  Most  of  the  sand  not  requiring  stripping  has  been  removed 
by  open  pit  methods,  the  pit  covering  more  than  an  acre.  Present 
mining  is  by  the  room  and  pillar  method,  similar  to  that  used  at  the 
Shepard  and  Newman  pits.  The  extent  of  the  workings,  size  of  rooms 
and  ])illars,  and  general  plan  is  nearly  the  same  as  in  the  Shepard  pit. 

Some  years  ago  an  experimental  washing  plant  was  built  near  this 
])it,  to  study  the  economic  possibilities  of  washing  the  sand  to  produce 
a  high-grade  clay  and  a  white  sand  as  separate  products.  The  experi- 
ments were  abandoned  for  various  reasons,  among  them  the  lack  of 
sufficient  water,  and  the  lack  of  profitable  market  for  the  sand. 

Sample  No.  134  was  taken  for  testing,  the  results  of  which  are  given 
on  page  261.  These  should  be  compared  with  the  results  on  samples 
No.  128,  129,  and  140. 

The  normal  production  of  Clark  sand  is  5000  to  7000  tons.  It  is 
loaded  by  hand  into  trucks  and  hauled  to  Carbondale. 

Doscn  Pit  :  The  Dosch  clay  pit  is  in  Lot  222  of  the  Arroyo  Seco 
grant,  near  the  lone-Sacramento  highway  at  a  point  three  miles  north- 
west of  lone,  and  one  mile  from  Clarksona  siding  on  the  Amador  branch 
of  the  Southern  Pacific  Railroad.  The  Dosch  clay  is  the  best  known  of 
the  lone  clays,  and  production  from  this  pit  is  considerably  greater  than 
from  any  otlier  plastic  clay  deposit  in  the  district. 

Two  varieties  of  clay  are  diiferentiated.  The  Dosch  stripping,  sample 
No.  135  (see  p.  312),  includes  the  upper  beds  that  are  more  or  less 
contaminated  by  surface  infiltration  of  water  carrying  iron  salts.  The 
thickness  varies,  but  is  usually  less  than  10  feet.  This  clay  is  useful  as 
an  ingredient  of  sewer-pipe  mixes.  The  Dosch  clay,  sample  No.  136  (see 
]).  302),  underlies  this  to  a  maximum  thickness  of  80  feet.  It  is  a 
])lastic  fireclay,  used  for  terra  cotta,  ])ottery,  and  stoneware.  At  the 
time  of  visit  in  1925  and  1926,  the  pit  was  about  an  acre  in  extent,  and 
the  height  of  the  face  was  40  feet.  Mining  is  by  steam  shovel,  loading 
into  5-ton  trucks.  Four  trucks  are  in  service  to  haul  the  clay  from  the 
pit  to  Clarksona,  where  it  is  stored  in  a  large  covered  warehouse,  and 
loaded  into  railroad  cars  as  needed  for  shipment.  A  supply  of  clay 
is  thus  available  during  the  winter  months,  Avhen  mining  is  stopped. 

The  production  is  4000  tons  of  Dosch  stripping  and  10,000  to  12,000 
tons  of  the  underlying  Dosch  clay  }ier  year. 

W.  S.  Dickey  Clay  Mannfacturinu  Company.  The  Fancher  pit, 
under  lea.se  to  the  AV.  S.  Dickey  coiu])any,  is  on  the  northerly  sloi)e 
of   Jackson    Vallev,   one    mile    west    of   Buena    Vista,    3.75    miles    air 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


59 


line  S.  3°  E.  from  lone,  or  5.1>  riiiles  by  road  south  of  Wallon  siding, 
on  the  Amador  Central  Railroad. 

Photo  No.  10-A  is  a  view  of  this  pit,  taken  on  August  8,  1925.  The 
strip])iiig  of  loose  sandy  and  gravelly  soil  attains  a  maximum  thickness 
of  2U  feet  in  the  present  pit,  but  will  gradually  increase  as  mining 
operations  advance  northward.  Two  varieties  of  clay  are  differentiated. 
The  upper  bed  (sample  No.  141),  six  to  ten  feet  thick,  is  a  yellowish 
fireclay,  containing  occasional  iron  stained  boulders.  This  is  underlain 
by  at  least  15  feet  of  hard  blue-gray  plastic  clay  (sample  No.  142), 
which  at  the  time  of  visit  was  not  in  use.  The  results  of  tests  on  these 
varieties  are  given  on  i)age  280. 

The  method  of  mining  ])revious  to  1927  is  clearly  illustrated  in  the 
pliotograph.  Hand  picking  and  light  blasting  was  used  to  loosen  tlie 
clay  from  tlie  bank,  wliere  it  was  picked  up  by  a  tractor-drawn  scraper, 
dragged  up  an  incline,  and  dumped  into  a  hopper  over  the  tunnel, 


Photo  No.   10-A.     Fancher  clay  pit,  Jackson  Valley,  near  lone,  leased  by  W.   S. 
Dickey   Clay   Mfg.    Co.,    facing   northwest.      (In    1925.)       (Samples   No.    141 
and  142.) 


from  which  it  was  delivered  to  an  auto  truck.  A  one-ton  Ford  truck  is 
used  for  hauling  the  clay  to  Wallon  siding.  Beginning  in  1927,  the 
thickness  of  overburden  has  been  such  that  the  mining  method  was 
changed  to  tunneling. 

Eckland  Property.  Mrs.  C.  Eckland,  1743  N.  Hunter  Street,  Stock- 
ton, owner.  This  property  consists  of  80  acres,  lying  to  the  south  of 
the  lone-Jackson  highway  at  the  point  where  it  crosses  the  railroad, 
1.5  miles  ea.st  of  lone.  The  property  is  at  present  (1927)  idle,  but 
was  at  one  time  worked  by  Mr.  Dennison  of  lone.  Yellow,  i)ink, 
and  red-mottled  plastic  clays  are  exposed  in  the  walls  of  the  abandoned 
pit,  from  which  sample  No.  213  was  taken  (see  page  299).  \Vm.  Haver- 
stick  of  lone  supplied  a  .sample  (No.  209,  p.  263)  of  white  sandy  clay 
from  a  16-foot  drill  hole  on  the  southwestern  portion  of  the  property. 
Almost  the  entire  property  is  covered  with  an  overburden  of  volcanic 


60 


DIVISION   OF   MINES  AND   MINING 


breccia,  and  insufficient   i)ros|)ecting  has  been   done  to  determine  tlie 
extent  and  character  of  the  underlying  clay  beds. 

lone  Fire  Brick  Co.,  J.  T.  Roberts,  president  and  general  manager, 
12  Russ  Building,  San  Francisco ;  Wm.  Brown,  superintendent  at 
lone.  The  lone  Fire  Brick  Co.,  a  subsidiary  of  the  Stockton  Fire  Brick 
Company,  is  located  about  two  miles  southeast  of  the  town  of  lone, 
on  a  spur  track  of  the  Amador  Central  Railroad.  JNIachine-made  fire 
brick  are  made,  using  a  mixture  of  Lincoln  clay,  now  secured  from 
the  pit  of  the  Clay  Corporation  of  California  at  Lincoln  (sample  No. 
280,  p.  305),  and  lone  clay,  sand  (sam])le  No.  140,  p.  280),  and  grog 
from  pits  near  the  plant. 


Photo  No.    10-B.     Brick  machinery  in  plant  of  lone  Fire  Brick  Company. 
(Photo  by  courtesy  of  the  company.) 

The  mixture  is  prepared  in  a  dry  pan  and  pug  mill,  shaped  in  an 
auger  machine,  wire  cut  (side),  and  repressed.  Drying  is  accomplished 
in  air  under  sheds  and  in  the  open.  Only  such  standard  shapes  as 
can  be  made  on  the  auger  machine  are  manufactured  at  this  plant,  there 
being  no  hand  molding.  Photo  No.  10-B  is  an  interior  view  of  the  plant, 
showing  an  auger  machine  and  two  re])resses,  with  off-beai'ing  con- 
veyors. 

The  firing  equipment  consists  of  five  oil-fired  round  down-draft 
kilns,  having  a  total  capacity  of  11,000  brick  per  day.  The  auger 
machine  capacity  is  20,000  brick  ])er  day,  which  makes  it  possible  to 
prepare  a  sur])lus  for  storage  to  be  fired  during  the  winter  months, 
when  clay  mining  can  not  be  economically  carried  on. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  61 

Groc:  Groo;  for  use  in  llic  phiiil  of  llic  lone  Fife  liriek  Company  is 
mined  fi"om  a  small  i)i1  adjoining-  the  Uacon  I'ed  day  i)i1.  A  six  to 
twelve  foot  bank  is  exposed,  over  a  len«rtli  of  100  fi'et.  'Phe  material 
consists  maiidy  of  i)artly-rounded  (piarl/  <>ravel,  most  of  Aviiieh  is 
under  two  inches  in  diameter.  The  interstices  are  partly  filled  with 
fine  sand,  with  a  small  amount  of  clay,  li'on  stainin«>'  is  a  ])rominent 
macroscopic  feature,  but  the  total  iron  content  is  not  too  high  to  permit 
the  production  of  .second-j>rade  fire  brick  when  used  as  the  sole  grog 
constituent. 

Sand:  The  sand  ])it  of  the  lone  Fire  Brick  Com])any  is  lu'ar  the 
grog  pit  and  is  shown  on  photo  No.  10-C. 

May  E.  Xewnum  Estate.  "Slain  otYice,  980  lUish  Street,  San  Fran- 
cisco. The  pit  is  on  a  150-acre  proi)erty  in  Sees.  20,  80,  and  .'U,  T.  6 
N.,  I\.  10  E.,  M.  D.  M.,  on  the  Amador  Central  Railroad,  one  mile  south- 
west from  lone,  and  less  than  a  half  mile  northeast  from  the  plant  of  the 
lone  Fire  Brick  Co. 

The  bulk  of  the  output  from  this  property  up  to  date  has  been  lone 
sand,  but  plastic  red  clay  beds  have  been  found,  and  a  small  amount 
has  been  shii)])ed.  The  main  sand  pit  abuts  the  railroad  tracks  on  its 
eastern  boundary.  The  sand  occurs  in  two  separate  beds  each  10  to  15 
feet  thick  and  separated  by  a  bed  of  carbonaceous  sand  from  6  to  30 
feet  thick.  Volcanic  breccia  of  variable  thickness  overlies  tha  deposit. 
Open-pit  mining  was  used  at  first,  but  practically  all  of  the  sand  not 
covered  by  volcanic  breccia  has  by  this  time  been  removed,  and  ])resent 
mining  is  by  underground  methods,  using  the  room  and  pillar  method. 

The  general  plan  of  mining,  M'henever  a  systematic  lay-out  is  possible, 
is  to  drive  rooms  in  the  bottom  of  the  upper  bed  approximately  10  by 
10  feet  in  cross-section  on  25  foot  centers  to  the  limit  of  the  block  of 
ground  being  mined,  usually  about  250  feet,  then  retreat  by  excavating 
to  the  roof,  and  by  cutting  across  to  adjacent  rooms,  finally  reducing  the 
j^illars  to  a])])roximately  six  feet  in  diameter.  The  sand  is  loaded  by 
liand  into  small  cars,  which  are  dumped  into  a  loading  chute  at  the 
entrance  of  the  mine.  The  loading  chute  delivers  to  mine  cars  which 
are  in  turn  hauled  up  an  incline  and  out  of  the  pit  by  a  car  hoist, 
finally  delivering  the  sand  to  a  loading  bin  on  the  railroad  siding. 

Some  of  the  lower  sand  bed  has  been  mined  and  shipped  from 
places  where  it  has  been  exposed  by  open-pit  mining.  The  present 
underground  method  does  not  leave  the  mine  in  a  satisfactory  condi- 
tion for  the  recovery  of  the  low^er  bed  in  the  future,  unless  the  capping 
of  volcaiiie  breccia  can  be  utilized  as  grog,  and  the  bed  of  carbonaceous 
sand  is  strip]ied.  Seven  or  eight  men  are  employed  during  the  dry 
months,  when  an  average  of  9  cars  per  week  is  ship])ed.  The  annual 
output  varies  with  demand,  and  is  normally  in  excess  of  6000  tons. 

Since  the  above  was  written,  the  property  was  visited  in  1927  by  Mr. 
Logan,  from  whose  report'  the  following  additional  notes  are  taken : 

"The  old  pits,  operated  for  years  south  of  the  track,  have  been  worked  up  to  the 
property  line.  A  new  i)it  has  recently  been  started  on  the  north  side  of  the  track. 
In  vertical  section,  so  far  as  opened,  it  shows  from  top  to  bottom  2.5  feet  of  over- 
burden 10  feet  of  red  mottled  clay,  and  15  feet  of  white  sand.  The  red  mottled 
clay  now  being  shipped  for  testing  (April  13)  is  said  to  carry  a  little  more  sand  than 
the  iAcon  mottled  clay.  Nine  men  were  employed  on  that  date.  Clay  is  mined  by 
hand  m  an  open  pit  and  hauled  in  a  small  truck  to  the  railroad  cars,  a  few  hundred 
feet  away.  It  is  thought  this  clay  will  prove  suitable  for  tile.  The  white  sand  is 
stated  to  run  71%  silica.  If  regular  production  starts,  drifts  will  be  .run  to  avoid 
handling  the  overburden." 

1  State  Mineralogist's  Rep.  XXIII,  p.   141. 


62 


DIVISION   OF    MINES   AND   MINING 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  63 

Three  samples  were  taken  from  tliis  property.  No.  129  is  sand 
from  the  upper  sand  bed,  taken  from  the  nnderjifround  -workings  at 
the  Avorking  face  when  visited  on  August  8,  192,").  The  test  results  are 
given  on  page  2()1.  Sample  Xo.  ].'}()  is  representative  of  the  carbonaceous 
sand,  and  was  taken  with  the  object  of  studying  possible  uses.  The 
test  results,  page  2!H),  on  tlie  untreated  sand  were  nnfavoi-abh'.  and  is 
unlikely  that  beneficiation,  even  if  proved  possible,  would  be  of  com- 
mercial importance  in  the  immediate  future.  Sample  No.  131  is  from 
the  deposit  of  red  clay  from  the  new  pit,  and  is  seen  (p.  329)  to  be  quite 
similar  in  its  jiroperties  to  the  Bacon  red  (sample  No.  127.  p.  335). 

Yosemite  Portland  Cement  Company.^  Main  office.  Pacific  Building, 
San  Francisco.  This  is  known  as  the  Harvey  ])it  and  is  part  of  over 
100  acres  of  land  recently  purchased  from  Fred  Harvey.  The  pit  is 
just  east  of  the  old  Ilarvev  coal  mine,  and  one  mile  north  of  Carbondale. 
The  land  is  in  Sees.  32,  33  et  al.,  T.  7  N.,  R.  9  E.,  M.  D.  M. 

Bluish  fireclay  occurs  with  an  overburden  of  from  two  to  three  feet 
of  soil  in  which  are  found  concretionary  boulders  of  red  iron  oxide. 
The  pit  was  formerly  operated  by  hand  methods,  but  in  1927  a  jViow 
and  scraper,  drawn  by  a  tractor,  were  used  for  removing  the  over- 
burden, and  the  clay  was  mined  by  a  small  steam  shovel.  The  pit  is 
now  about  12  feet  deep,  and  it  is  stated  that  borings  have  indicated 
a  depth  of  65  feet  of  clay,  over  an  extensive  area.  Auto  trucks  are 
used  to  deliver  the  clay  to  the  railroad. 

The  clay  contains  about  32%  alumina,  dry  basis,  and  is  used  in  the 
manufacture  of  white  cement.  It  is  also  a  useful  sewer  pipe  and 
terra  cotta  clay. 

Sample  No.  133  Avas  taken  for  test.  The  results  are  given  on  page 
298. 

Changes  Since  Former  Reports. 

The  following  important  changes  have  occurred  in  the  Amador 
County  clay  industry  since  the  publication  of  Preliminary  Report  7, 
and  the  Nineteenth  Report  of  the  State  Mineralogist : 

Amador  Kaolin  Company.     Extinct. 

W.  D.  Amirk  Property  (formerly  operated  by  the  Philadelphia 
Quartz  Co.).  A  white  sand  deposit  containing  from  20%  to  30%  of 
kaolin.  A  washing  plant  was  built  and  operated  during  the  World 
War.     Now  dismantled  and  idle. 

McKissick  Cattle  Company.  Former  owner  of  Rancho  Arroyo  Seco, 
now  ow^ned  by  S.  E.  Kieffer  and  leased  by  U.  A.  Starkweather,  as  noted, 
ante. 

Newman  Clay  Company.     Now  ]\Iay  E.  Newman  Estate. 

Philadelphia  Quartz  Company.     No  longer  operating  in  the  county 

Bibl.  of  lone  district :  Cal.  State  Min.  Bur.  Report  XIV,  pp.  5-11 ; 
XXIII,  pp.  134-144.  Bull.  No.  38,  p.  206.  Prel.  Rept.  No.  7, 
p.  38. 


'  Logan,   C.   A.,  op.   cit.,  p.    138.      (Under  Pacific   Poi-tland   Cement   Company,   Con- 
solidated.) 


64  DIVISIOX   OF    MINES   AND   MINING 

BUTTE  COUNTY. 
General    Features. 

Butte  County  is  in  the  north-central  jiortion  of  the  state,  lar<iely 
between  the  Sacramento  and  Feather  rivers.  Its  -western  half  is  in 
the  Sacramento  River  basin  and  its  eastern  half  is  in  the  foothills  of 
the  Sierra  Nevada  ^Mountains.  The  area  of  the  county  is  1722  square 
miles  and  its  population  is  30,030  (1920  census). 

Among  the  mineral  resources  of  the  county  are  asbestos,  barytes, 
chromite,  gems,  gold,  limestone,  niarbl^,  mineral  ^vate^,  platinum 
group,  silver,  and  miscellaneous  stone.  The  following  are  produced 
commercially  at  present:  gold,  miscellaneous  stone,  platinum,  silver, 
mineral  water,  brick,  coi)per,  gems  (diamonds),  lead,  natural  gas,  and 
soa])stone. 

Clay    Resources. 

Deposits  of  high-grade  clay  have  been  reported  from  numerous  local- 
ities in  Butte  County,  especially  within  a  radius  of  12  miles  from 
Oroville,  the  count.y  seat,  but  only  one  of  these  has  been  developed. 
Common  brick  claj's  are  plentiful  at  many  places  in  the  valley  region 
east  of  the  Sacramento  River,  and  northwest  of  the  Feather  River,  and 
in  some  of  the  Neocene  River  channels  at  higher  elevation. 

Beginning  at  a  point  two  miles  north  of  Oroville,  and  extending 
northward  for  nearly  eight  miles  to  Pentz  and  Cherokee,  the  lone 
formation  has  been  traced.^  The  geologic  history  of  this  region  has 
been  summarized  by  Lindgren  as  follows : 

"(1)  Deposition  of  Chico  formation  (Upper  Cretaceous)  ;  (2)  epoch  of  erosion; 
(3)  accumulation  of  lowest  gold-bearing  gravels  (Eocene?)  ;  (4)  deposition  of  lone 
formation,  underlying  Table  Mountain;  (5)  eruption  of  basalt  of  Table  Mountain; 
(6)  formation  of  high  volcanic  gravels  of  Table  Mountain;  (7)  epoch  of  erosion;  (8) 
deposition  of  tuff  and  lower  gravels  (late  Pliocene)  of  Oroville;  (9)  epoch  of  erosion; 
(10)  deposition  of  bench  gravels  of  Oroville  (Quaternary);  (11)  epoch  of  erosion; 
(12)  deposition  of  present  stream  gravels.  The  epoch  of  erosion  (item  7  above)  fol- 
lowing the  formation  of  the  high  volcanic  gravels  in  many  places  removed  a  part  of  the 
lone  formation  and  basalt  before  the  deposition  of  tuff.  The  lone  formation  itself 
was  laid  down  on  a  very  uneven  surface." 

As  a  result  of  the  foregoing  geologic  lii.story,  it  is  possible  that  many 
of  the  occurrences  of  high-grade  clay  that  have  been  reported  are  small 
and  irregular,  although  in  most  localities  thorough  prospecting  by 
drilling  will  be  necessary  in  order  to  determine  the  size,  shape,  and 
quality  of  the  deposit,  as  very  little  information  can  be  gleaned  by 
surface  examination.  So  far  as  known,  the  only  property  in  the  Tone 
formation  that  has  been  well  prospected  is  that  of  the  Table  ^Mountain 
Clay  Products  Co.  near  Wick,  where  a  sufficient  quantity  of  good  clay 
was  found  to  warrant  the  erection  of  a  plant. 

A  number  of  localities  south  and  southeast  of  Oroville  were  investi- 
gated, and  samples  were  taken  of  some  of  the  typical  materials  of  pos- 
sible ceramic  utility.  Some  of  these  proved  to  be  derivatives  of  the 
rhyolitic  and  andesitic  flows,  with  little  or  no  ceramic  value.  The 
nature  of  such  deposits  is  discussed  more  fully  in  the  descriptions  of 
depo.sits  in  Nevada  and  Placer  counties. 

Some  clay  from  settling-ponds  left  by  the  dredges  that  formerly 
operated  near  Oroville  has  been  mined  and  shipped  to  various  ceramic 
plants,  especially  to  the  Gladding,  McBean  &  Co.,  plant  at  Lincoln, 

>  Lindgren,  Waldemar.  The  Tertiary  Gravels  of  the  Sierra  Nevada  of  California  : 
Prof.  Paper  73,  U.  S.  Geol.  Survey,  p.  86,  and  Plate  XV,  1911. 


CLAY  RESOURCES  AND  CERA^MIC  IXDTTSTRY  65 

l*lacer  County,  but  the  new  (■iit('r])i'isc  of  the  Natonia  Clay  Co.,  at 
Xatonia.  Sacramento  County  (see  pa<re  lS(i),  will  doubtless  render  sueli 
operations  nni)J'ofital)le  in  Oroville. 

One  common  l)riek  plant  near  Palermo  sui)plies  the  needs  of  tliis 
region  for  common  buildin<?  brick. 

The  Lund  Brick  Yard  is  on  the  Nelson  E.  Lund  ranch,  .3.6  miles 
by  road  east  of  the  Palermo-IIoncut  road  from  a  point  4.4  miles  south- 
east of  Palermo,  a  total  of  13.7  miles  by  road  southeast  from  Oroville. 
At  the  time  of  visit,  on  August  24,  1925,  the  first  successful  burn  of 
common  red  brick  had  been  completed.  Mr.  Lund  expects  to  manu- 
facture ruffled  face  brick  if  the  local  demand  warrants. 

The  clay  is  mined  by  hand  methods  from  a  deposit  of  clay  and  silt 
that  comprises  the  upper  i)art  of  a  Tertiarj^  river  channel  deposit, 
parts  of  which  were  formerly  hydraulicked  for  gold.  Three  distinct 
variations  of  sand-gravel-clay  beds  are  exposed  in  the  pit.  The  upper 
bed  is  from  one  to  three  feet  thick,  and  consists  of  fine-grained  red- 
colored  plastic  cla}',  with  little  sand  and  few  pebbles.  Tlie  middle 
bed  contains  more  sand,  and  some  fine  gravel,  and  is  from  three  to 
four  feet  thick.  The  lower  bed,  of  unknown  thickness,  is  too  sandy 
to  work  alone,  and  contains  considerable  fine  gravel,  and  some  larger 
boulders.  Each  of  these  beds  was  sampled  separately,  under  the  sample 
numbers  178-,  1,  2,  and  3,  respectively,  from  the  top  down.  The  middle 
bed  gives  the  best  results  for  brick-making  and  the  top  bed  is  character- 
ized by  high  shrinkage  and  danger  of  cracking  during  drying  and 
firing.  A  reasonably  uniform  product  can  be  obtained  by  inelutling  a 
sufficient  proportion  of  the  sandier  bottom  bed  to  offset  the  high  shrink- 
age of  the  top  bed,  but  on  account  of  extreme  and  sudden  variations  in 
the  character  and  thickness  of  each  of  the  beds,  this  may  be  difficult 
unless  a  method  of  bedding  and  reclaiming  is  used  in  the  plant.  See 
page  325  for  the  results  of  test. 

Tlie  plant  is  equipped  with  a  bucket  elevator  for  delivering  the 
material  from  the  pit  to  a  roll  cruslKM-.  This  is  followed  by  double 
pugging,  and  an  auger  machine  of  2(),()U0  brick  daily  capacity.  Power 
is  supplied  by  steam  from  an  oil-fired  boiler.  The  clay  is  worked  in  a 
softer  state  than  is  commonly  used  with  auger  machines.  Drying  is 
done  under  sheds.  Care  must  be  taken  to  avoid  ex])osure  of  the  brick 
to  sun  and  hot  wind  during  drying,  as  serious  drying  cracks  may 
develop. 

An  oil-fired  kiln  is  used  for  firing.  Steam  is  used  for  atomizing  the 
oil.  In  the  10-ft.  by  20-ft.  kiln  in  use  at  the  time  of  visit,  the  firing 
required  seven  days,  and  the  kiln  cooled  in  four  to  five  days. 

The  plant  is  operated  as  needed  to  supply  the  local  demand. 

Table  Mountain  Clay  Products  Co.  L.  F.  Riley,  president;  H.  M. 
Gamble,  superintendent.  Home  address,  Oroville.  This  company  has 
acquired  and  developed  a  clay  deposit  in  the  SW|-  of  Sec.  22,  T.  20  N., 
R.  3  E.,  ^I.  D.  ]\L,  and  at  the  time  of  visit  on  August  24,  1925,  were 
constructing  a  plant  for  the  manufacture  of  face  brick,  hollow  tile, 
and  roof  tile.  The  plant  lies  0.4  mile  w^est  of  the  Oroville-Pentz  high- 
way, from  a  ]ioint  5.9  miles  by  road  northwest  from  the  center  of 
Oroville. 

The  property  was  prospected  by  means  of  auger  holes,  most  of  which 
varied  from  14  to  22  feet  deep.    Clay  was  found  under  a  large  portion 

5—54979 


66  DIVISION   OF    MINES   AND   MINING 

of  the  property,  underlying  a  A-ariable  amount  of  basaltic  cappinf?. 
None  of  the  holes  penetrated  to  the  bottom  of  the  clay  beds,  and  it  is 
claimed  that  one  hole  was  drilled  to  a  depth  of  72  feet  without 
encounterinji:  a  change  of  formation. 

The  overburden  coverino-  a  large  portion  of  the  area  is  only  6  inches 
to  2  feet  in  thickness,  and  mining  operations  will  at  first  be  confined 
to  this  ground.  Mining  is  done  with  horse  scrapers,  delivering  the  clay 
to  belt  conveyors  which  are  extended  as  the  pit  advances. 

The  clay  is  crushed  in  rolls,  mixed  in  a  pug-mill,  and  the  products  are 
shaped  on  an  auger-machine  having  a  capacity  of  40,000  brick  per  day. 
A  dry  pan  may  later  be  added  ahead  of  the  pug-mill.  Drying  is  done 
under  sheds  in  the  open  air.     The  kilns  are  fired  with  oil. 

►Sample  Xo.  ITo  was  taken  for  test,  the  results  of  which  are  on  page 
304. 

Undeveloped    Deposits. 

Two  samples  were  taken  from  alongside  the  Oroville-Quincy  road. 
No.  176  (see  page  825)  is  a  decomposed  igneous  rock,  considerably 
kaolinized,  and  badly  iron-stained,  from  an  exposure  4.3  miles  by  road 
southeast  from  the  center  of  Oroville,  in  Sec.  13,  T.  19  N.,  R.  4  E., 
M.  D.  M.  The  sample  probably  contains  more  iron  oxide  than  would 
be  found  in  the  body  of  the  deposit.  The  size  of  the  deposit  could  not 
be  estimated,  but  the  occurrence  is  such  as  to  indicate  a  good  tonnage. 
The  material  is  suitable  for  the  manufacture  of  red  brick.  Another 
sample,  No.  177  (see  page  336),  was  taken  from  a  road  cut,  2.9  miles 
from  the  center  of  Oroville.  It  is  high  in  volcanic  ash,  but  contains 
enough  alluvial  clav  and  silt  to  make  it  usable  to  a  limited  extent  in 
the  manufacture  of  red  brick,  if  mixed  with  a  more  })lastic  clay.  The 
extent  of  the  dei)osit  was  indeterminate. 

An  unsuccessful  attempt  was  made  to  secure  recent  information 
regarding  the  deposits  mentioned  in  previous  reports  of  the  Bureau.^ 
All  of  these  reports  were  made  previous  to  1906,  and  in  the  limited 
time  available  for  the  present  investigation,  it  was  impossible  to  find 
anyone  in  the  various  localities  mentioned  who  had  any  knowledge  of 
the  existence  of  clay  deposits,  or  who  were  able  to  give  information 
regarding  the  former  ow^ners  of  these  deposits.  For  the  sake  of  com- 
pleteness, these  reported  occurrences  are  listed  hereunder,  wuth  such 
notations  that  seem  of  interest  at  the  present. 

Bohannon  Ranch,  Yankee  Hill.  Sec.  4,  T.  21  N.,  R.  5  E.,  M.  D.  M. 
"Large  body  of  plastic  yellow  clay,  tenacious  and  refractory."  This 
lies  in  the  Big  Bend  of  the  Feather  River,  probably  at  an  elevation  of 
over  1000  feet  above  the  bottom  of  the  canyon.  If  of  economic  value, 
clay  could  be  delivered  by  pack-train  or  tramway  to  the  Western  Pacific 
railroad,  a  distance  of  probably  two  miles.  The  result  of  inquiry 
among  residents  of  Yankee  Hill  did  not  warrant  an  attempt  to  find 
the  property.  The  mere  fact  that  it  was  described  as  "yellow,"  and 
that  it  is  in  such  an  isolated  region  preclude  the  possibility  of  economic 
utilization  for  many  years  to  come. 

Biggs.  (Max  Brooks  and  Mr.  Reed,  reported  owners).  Sec.  19  and 
30,  T.  18  N.,  R.  3  E.,  "Light  brown  and  wdiite,  brittle  clay,  about 

'  Cal.  State  Min.  Bur.  Prel.  Rept.  No.  7,  p.  43,  which  summarize.s  the  data  given  in 
Bulletin  No.   38,  p.  211. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  67 

one-half  mile  wide."  This  is  now  included  in  the  Butte  County  Farms. 
Mr.  II.  II.  ({rimos,  tli(^  luanapTr,  kindly  uiidoTtook  an  inquiry  amono: 
old-time  residents  and  employees  in  the  vicinity,  and  re])orted  tliat 
nothing:  was  known  of  such  a  deposit,  and  that  the  previous  report 
may  have  referred  to  a  wide  belt  of  hard-pan  that  comes  close  to  the 
alluvial  surface  of  the  ground  over  portions  of  the  property. 

Coal  Canon.  Sec.  12,  T.  20  N.,  R.  3  E.,  "A  stratum  of  clay  in  a 
coal  mine."  This  probably  refers  to  an  abandoned  and  inaccessible 
coal  mine  in  the  lone  formation  nnderlyinp-  Table  ^Mountain.  The 
property  is  2.5  miles  northeast  of  the  i)lant  of  the  Table  Mountain 
Clay  Products  Co. 

Durhin  Ranch.  SWj  Sec.  13,  T.  21  N.,  R.  3  E.,  "Large  deposit  of 
refractory  clay,  with  low  ])lasticity.  Total  dei>th  100  ft."  Also, 
"*  *  *  a  deposit  of  light-colored  clay,  more  plastic  than  above  in 
XEj,  Sec.  13."  This  would  lie  one  mile  north  of  Pentz.  A  recon- 
naissance of  this  section  was  made,  without  finding  any  material  of 
value.  Most  of  the  section  is  covered  with  Tuscan  tuff.  The  lone  for- 
mation outcrops  to  the  south,  and  disappears  under  the  Tuscan  tuff. 

Garden  Ranch.  SWj  Sec.  22.  T.  19  N.,  R.  3  E.,  3  miles  southeast 
of  Oroville.  "Extensive  deposits  exposed  in  road  building."  No 
material  of  value  could  be  found  on  this  area. 

Snow  Ranch,  Lovelocks.  SWj  Sec.  31,  T.  24  N.,  R.  4  E.,  "Light- 
colored  clays  of  medium  plasticity."  A  reconnaissance  of  this  locality 
was  made,  and  nothing  of  interest  was  found.  Some  partly  kaolinized 
diabase  (  ?)  occurs  in  ])laces,  but  is  badly  contaminated  with  iron.  The 
region  is  too  inaccessible  to  be  of  economic  importance  as  a  producer 
of  any  but  the  finest  grades  of  clay. 


CALAVERAS  COUNTY. 
General    Features.' 

Calaveras  County  lies  on  the  west  slope  of  the  Sierra  Nevada  Moun- 
tains, the  elevation  ranging  from  400  feet  above  sea  level,  where  it  joins 
San  Joaquin  County  on  the  west,  to  8000  feet  where  the  eastern  bound- 
ary rests  on  the  summits  of  the  Sierras  adjoining  Alpine  County. 
Bounded  on  the  north  by  Amador  County  and  on  the  south  by 
Tuolumne,  it  shares  with  them  the  advantage  of  a  climate  where  snow 
seldom  falls  and  practically  never  lies  below  2500  feet  elevation,  and 
where  mining  may  be  carried  on  throughout  the  j'ear  under  ideal 
weather  conditions. 

Water,  power,  and  timber  resources  are  plentiful.  Several  railroad 
branches  connect  the  main  towns  with  points  in  the  San  Joaquin  Valley. 
Most  points  in  the  county  at  elevations  under  2500  feet  can  be  reached 
by  automobile  during  the  greater  part  of  the  year. 

The  principal  mineral  .products  of  the  county  are  gold  and  copper. 
Other  minerals  that  have  been  produced  are  silver,  produced  as  a 
by-product  of  gold  and  copper  mining,  limestone,  mineral  paint,  clay, 
mineral  water,  asbestos,  rock  crystal  (quartz),  chromite,  and  miscel- 
laneous stone. 


'Prom  Logan,  C  A.,  Calaveras  County:   State  Mineralogist's  Report  XXI,  p.   135, 
1925. 


68  DIVISION  OF   MINES  AND  MINING 

Geology. 

The  geoloyy  of  the  county  is  similar  to  that  of  Amador  County  and 
others  in  the  Mother  Lode  belt.  The  lone  formation  (Eocene)  is  found 
at  numerous  places,  but  is  not  so  extensively  developed,  nor  so  well  pre- 
served as  in  Amador  County.  The  following  is  a  portion  of  the 
geological  summary  of  the  county  as  given  by  Logan  :^ 

"The  Neocene  shore-line,  as  Indicated  by  the  lone  formation,  covered  the  county 
from  Lancha  Plana  through  Valley  Spring  to  .Jenny  Lind,  and  southward  to  Milton. 
The  most  westerly  of  the  lode  mining  districts  are  the  Hog  Mountain-Gopher  Range 
cojiper  mining  district,  where  copper  ores  occur  in  diabase  and  allied  rocks,  near 
the  southwest  corner  of  the  county,  and  the  Campo  Seco  copper  district,  where 
similar  ores  occur  in  amphibolite  schist.  In  a  depression  called  Salt  Spring  Valley, 
between  the  older  crystalline  rocks  of  Gopher  Ridge  and  Bear  Mountains,  lies  a 
belt  of  black  Mariposa  slate  with  interbedded  lenses  of  ami)hibolite,  with  important 
copper  deposits,  which  conform  in  strike  with  the  direction  of  schistosity  of  the  enclos- 
ing rocks.  The  Mother  Lode  belt  of  black  Mariposa  slate  enters  the  county  at 
Middle  Bar,  but  aside  from  the  Gwin  Mine,  which  had  reached  a  depth  of  2Sr)0  feet 
before  it  was  closed  several  years  ago,  little  deep  mining  has  been  done  in  this 
district,  though  numerous  quartz  mines  have  been  opened  to  depths  of  less  than  1000 
feet.  There  are  many  ijrominent  veins  in  the  granodiorite  area  of  Mokelumne  Hill, 
but  the  main  belt  passes  southeast,  a  line  of  Assuring  having  passed  into  the  amphib- 
olite schist,  in  which  rock  were  found  the  deep  mines  of  Angels  Camp  and  Carson 
Hill. 

"The  East  Belt  is  a  general  name  given  to  the  gold-quartz  mining  districts  in  the 
great  body  of  Calaveras  (Carboniferous)  rocks,  lying  east  of  the  younger  Mother 
Lode  slate  and  east  of  the  amphibolite  schists  accompanying  the  Mariposa  slate. 
The  Calaveras  rocks  are  chiefly  hard  blocky  siliceous  and  micaceous  schists,  quartzite, 
curly  black  slates  and  accompanying  intrusive   dikes,   usually  of  basic  character." 

Clay   Resources. 

Various  clay  deposits  in  the  lone  formation  near  Valley  Springs  and 
Helisma  have  been  operated  in  the  past.  Some  work  has  been  done 
recently  on  a  deposit  of  kaolinized  talc  schist  in  the  Calaveras  (?) 
formation. 

The  California  Pottery  Co.y  of  Oakland  and  IMerced,  own  two  deposits 
in  Calaveras  County,  one  at  Nigger  Hill,  and  the  other  at  Valley 
Springs.    Henry  Ward  of  Vallej^  Springs  is  superintendent. 

Nigger  Hill  :  Near  Nigger  Hill,  about  three  miles  north  of  Valley 
Springs,  a  good  deposit  of  white-burning  kaolinized  sericite  schist  has 
been  discovered.  A  tunnel  has  been  driven  for  250  feet.  The  kaolin- 
ized zone  is  from  15  to  25  feet  thick.  The  material  has  low  plasticity, 
but  is  of  use  as  a  filler  in  white  tile  bodies. 

Sample  No.  236  (p.  263)  was  taken  at  the  face  of  the  tunnel,  and 
Sample  No.  237  (p.  263)  was  taken  at  the  portal. 

Valley  Springs  Clay  Pit  :  This  pit  is  ^  mile  northwest  from  Valley 
Springs  on  a  spur  track  from  the  Valley  Springs  branch  of  the  Southern 
Pacific  Railroad.  The  property  comprises  17  acres.  Fireclay  from  the 
lone  formation  is  mined  from  an  open  pit,  shown  in  photo  No.  11.  Two 
distinct  varieties  of  clay  are  mined  and  shipped  to  the  Merced  plant  of 
the  companj'.  One  of  the.se  is  classed  as  'pink  mottled,'  (sample  No. 
202.  ]).  337),  and  the  other  is  'yellow'  (sample  No.  203,  p.  337).  The 
two  varieties  are  somewhat  intermingled,  but  can  be  separated  by 
hand  as  mined.  In  the  southern  end  of  the  pit,  northward  to  the 
break  in  the  face  shown  in  the  photo,  the  pink  mottled  predominates, 
and  in  the  northern  end  of  the  pit,  the  yellow  variety  is  more  important. 
Some  yellow  sandy  streaks  traverse  the  clay,  and  in  places  small 
quantities  of  white  claj^  are  found. 

'  Ov.  fit.,  p.  140. 


CLAY  RESOURCES  AND  CERA:MIC  INDUSTRY 


69 


The  floor  of  the  pit  is  approximately  200  ft.  square,  and  the  face 
varies  from  10  to  30  feet  high.  The  clay  is  loosened  by  hand  drillinp; 
and  light  blasting,  and  is  loaded  by  hand  shoveling  into  ■wlicolbarrows, 
"which  are  dumped  into  a  hopper.  An  inclined  belt  conveyor  trans- 
ports the  clay  from  the  hopper  to  a  railroad  car. 

In  a  test  pit  five  feet  deep,  just  east  of  the  track,  ])ink  mottled  clay 
is  exposed.  Fifty  feet  farther  east  another  test-]iit  was  snnlc,  Avitli  the 
aid  of  a  Avindlass,  to  a  doptli  of  25  feet.  Uoth  i)iidv-mottled  and  yellow 
clay  were  found  to  the  bottom  of  the  shaft.  From  the  debris  surround- 
ing the  collar  of  the  test-pit  it  was  estimated  that  the  pink-mottled 
variety  comjirised  about  one-third  of  the  material  excavated.  A  third 
25-ft.  test  pit  was  dug  100  feet  north  of  the  second  one,  and  similar 
material  was  encountered,  in  addition  to  a  bluish-white  plastic  clay, 
not  entirely  free  fioin  liiiionitie  stains  (sample  No.  204,  p.  299).     This 


Photo  No.  11.  Valley  Springs  clay  pit  (California  Pottery  Co.),  facing  west. 
The  track  runs  S.  25°  E.  The  5-ft.  test-pit  appears  in  the  center  foregi-ound. 
(Samples  No.  202-204.) 


test-pit  was  bottomed  in  a  yellowish  sandy  bed.  From  the  evidence  on 
the  dump,  the  bluish-white  variety  of  clay  predominates  at  this  point. 

It  is  evident  that  the  total  thickness  of  useful  clay  is  in  excess  of 
50  feet,  and  the  structural  and  topographic  features  are  such  as  to 
warrant  the  expectation  that  these  beds  underlie  an  area  of  many  acres. 

Three  men  are  employed  during  the  operating  season.  In  1925,  nearly 
200  cars  were  shipped,  at  the  rate  of  approximately  four  cars  per  week. 

Helis'tna  Fireclay  Depo.'iif.  One-quarter  mile  north  of  Helisma 
(formerly  Burson)  station  on  the  Valley  Springs  branch  of  the 
Southern  Pacific  Railroad  is  an  abandoned  fireclay  pit  formerly 
controlled  by  W.  A.  Houts,  202  Balboa  Building,  San  Francisco. 
The  present  ownership  of  the  property  was  not  determined.  The 
deposit  is  in  the  lone  formation.  The  total  thickness  of  clay  exposed 
in  the  pit  varies  from  8  to  15  ft.  The  upper  part  of  the  clay  bed 
is  a  bluish-white  clay  with  good  plasticity,  and  the  lower  part  is  a 


70  DIVISION  OF   MINES  AND   MINING 

greenish-white  clay,  with  less  plasticity.  Both  varieties  of  clay  are 
traversed  by  thin  limonitie  seams  a  foot  or  more  apart. 

The  main  pit  is  150  ft.  lonp:,  50  ft.  wide  and  from  8  to  15  feet  deep. 
The  overburden,  of  volcanic  breccia,  increases  from  a  few  inches  at 
the  lower  edge  of  the  pit  to  10  ft.  at  the  upper  edge.  Two  hundred  feet 
to  the  west  is  a  smaller  pit  80  ft.  long  by  30  ft.  wide,  and  a  maximum  of 
10  ft.  deep.  The  clay  is  similar  to  that  in  the  larger  pit,  but  contains 
more  iron,  and  is  more  sandy. 

The  clay  was  formerly  worked  by  hand  loading  into  cars  which  were 
hauled  up  a  gentle  incline  to  a  loading  chute  overlooking  a  railroad 
siding.    All  equipment  has  been  removed  from  the  property. 

The  probable  extent  of  the  clay  bed  beyond  the  existing  exposures 
could  not  be  determined  without  boring,  on  account  of  the  overburden. 
Structural  features  are  favorable  to  a  continuance  of  the  clay  under  the 
low  hill  on  which  the  pit  is  located,  but  the  overburden  covering  the  top 
of  the  hill  may  be  20  ft,  or  more  in  thickness. 

Sample  No.  201.  page  305,  includes  both  types  of  clay  from  the 
main  pit. 

Bibl :  Cal.  State  Miu.  Bur.  Prel.  Kept.  No.  7,  p.  43. 

Pcnn  Mining  Co.  During  the  operation  of  the  copper  smelter  at 
Campo  Seco,  a  kaolinized  sericite  schist  overlying  the  copper  beds  was 
used  in  the  smelter  as  a  refractory.  Since  the  smelter  was  closed  down 
this  material  has  not  been  utilized.  The  locality  was  visited  on  Septem- 
ber 22,  1926,  and  a  sample  was  taken  from  the  abandoned  open  cut 
from  which  it  was  formerly  obtained.  The  sample  is  Xo.  238  and  the 
tests  demonstrate  that  the  plasticity  and  strength  are  low,  and  that  the 
content  of  fluxes  is  high,  causing  fusion  to  begin  at  cone  9  (1285°  C). 
See  page  316. 

Bibl:  State  Min.  Bur.  Bull.  38,  p.  211  ;  Prel.  Kept.  7.  p.  43. 

Texas  Mining  Compan}/.  J.  P.  Hoskinson,  Valley  Springs.  This  is 
an  undeveloped  property  about  two  miles  north  of  Valley  Springs. 
Small  exposures  of  sandy  fireclay  belonging  to  the  lone  formation  have 
been  found,  and  some  prospecting  has  also  been  done  on  an  outcrop  of 
kaolinized  sericite  schist  of  Calaveras  (?)  (Carboniferous)  age.  Sample 
Xo.  233  was  taken  of  the  fireclay,  but  was  not  tested,  as  the  quality  was 
obviously  poor,  and  the  continuity  of  the  deposit  is  doubtful.  Sample 
No.  234  and  235  were  taken  from  two  different  exposures  of  the  kaolin- 
ized schist.  The  test  results  of  X"o.  235  are  given  on  page  263.  It  is  a 
white-burning  refractory  material  of  low  plasticity,  that  would  be 
useful  as  a  filler  in  white  ceramic  bodies.  X'^o.  234  wa.s  not  tested,  as  it 
is  similar  to  No.  235. 

COLUSA  COUNTY. 
General    Features. 

Colusa  County  lies  on  the  west  side  of  the  Sacramento  Valley.  The 
west  side  of  the  county  is  in  the  foothills  of  the  Coast  Range,  and  the 
east  side  is  in  the  basin  of  the  Sacramento  Valley.  The  area  of  the 
county  is  1140  square  miles,  and  the  population  is  9920  (1920  census). 
Colusa  is  the  county  .seat  and  principal  town. 

The  mineral  resources  of  (^olusa  County  are  largely  undeveloped. 
Occurrences  of  coal,   chromite,   copper,   gypsum,   manganese,   mineral 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  71 

•water,  ])yrite.  ciincksilver,  sandstoni',  iiiiseellaneous  stone,  sulplnir.  and 
in  some  places,  <i:ol(l  and  silver,  are  known.  Of  these,  the  only  commer- 
cial production  is  of  minei-al  water,  sandstone,  and  miscellaneous  stone. 

Clay    Resources. 

Common  clays  suitable  for  the  manufacture  of  brick  are  abundant, 
but  there  is  at  present  no  local  industry.  A  bi'iek  yard  was  at  one 
time  operated  at  Colusa  by  George  Smith. 

Bibl:  State  Mineralogist's  Kept.  VIII,  p.   15!);  State  Min.  Bur. 
Bull.  38,  p.  242 ;  Prel.  Kept.  7,  p.  44. 


CONTRA   COSTA  COUNTY. 
General  Features.' 

Contra  Costa  is  one  of  the  East  Bay  counties  and  is  bounded  on 
the  west  and  north  by  the  waters  of  San  Francisco,  San  Pablo  and 
Suisun  bays  and  San  Joaquin  River.  San  Joaquin  County  is  on  the 
east  and  Alameda  County  is  on  the  south. 

The  area  of  the  county  is  714  square  miles,  about  half  of  which  is 
under  cultivation.  The  population  in  1920  was  53,889.  Its  industrial 
and  sliipping  activities  are  extensive.  The  county  has  approximately 
70  miles  of  deep  w'ater-front  on  which  are  located  nine  port  cities  in 
whicli  have  been  established  many  chemical  and  industrial  woi'ks. 
Agriculture,  stock  raising,  and  to  a  le.sser  extent,  mining,  contribute  to 
the  prosperity  of  the  county. 

Topographically,  Contra  Costa  County  is  distinguished  by  containing 
tlie  most  prominent  landmark  in  the  central  coast  counties,  Mt. 
Diablo,  which  rises  to  an  elevation  of  3849  feet  above  sea  level.  This 
peak  is  in  the  eastern  part  of  the  two  main  ridges  of  the  Coast  Range 
Mountains,  which  strike  northwesterlj'  across  the  county.  The  western 
ridge  lies  close  to  the  coast.  Its  crest  is  more  regular  but  its  highest 
peaks  are  less  than  2000  feet  in  elevation.  The  western  flank  slopes 
gently  towai'd  San  Francisco  Bay.  Between  the  eastern  and  w^estern 
ridges  lies  San  Ramon  Valley,  drained  by  San  Ramon  Creek,  which 
flows  northward  into  Walnut  Creek  and  hence  into  Suisun  Bay. 
Marsh  Creek  rises  on  the  eastern  slope  of  Mt.  Diablo  and  tlow's  north- 
easterly into  the  San  Joaquin  River.  These  are  the  two  principal 
streams  in  the  county.  The  northeastern  corner  of  the  county  is 
included  in  the  delta  area  of  San  Joaquin  Valley  and  is  elevated  only 
slightly  above  sea  level. 

Geology. 

Tliat  portion  of  the  Coast  Range  within  Contra  Costa  County  has 
been  studied  by  the  Department  of  Geology  and  Paleontology  of  the 
T^niversity  of  California,  and  the  soutlieastern  portion  has  been  mapped 
by  Lawson.- 

A  nearly  complete  section  of  the  Coast  Range  formations  from  the 
Franciscan  to  the  recent  are  exposed  within  the  county,  but  as  the  area 
is  one  of  many  faults,  no  single  formation  is  continuous  over  a  large 

'  From  Laizure,  C.  McK..  Contra  Ccsta  Countv  :  State  Mineralogist's  Rept.  XXIII, 
p.    2.    1927. 

-  Lawson,  A.  C.  San  Francisco  Folio,  No.  193,  U.  S.  Geol.  Survey. 


72 


DIVISION   OF   MINES   AND   MINING 


area.    The  most  abundant  strata  are  sandstones  and  shales  of  Cretaceous 
and  Tertiarj^  age. 

Contra  Costa  County  is  lacking  in  deposits  of  valuable  metals,  but 
its  structural  materials  are  important  natural  resources  on  account  of 
their  easy  accessibility  and  proximity  to  the  cities  surrounding  San 
Francisco  Bay.  Its  coal  deposits  are  of  potential  value.  The  most 
im]K)rt;int  minerals  now  produced  are :  cement,  miscellaneous  stone 
(crushed  rock,  sand,  and  gravel),  and  brick.  Claj',  limestone,  mineral 
water,  and  foundry  sand  are  also  on  the  commercial  list.  Other  mineral 
resources  include  asbestos,  coal,  copi)er,  diatomaceous  earth,  manganese, 
and  quicksilver. 

Clay    Resources. 

Alluvial  clay  and  silt  are  not  abundant  in  those  parts  of  the  county 
that  are  favorably  situated  with  respect  to  manufacturing  and  market- 
ing conditions.     However,  there  is  an  abundance  of  Tertiary  clay  shale 


Photo  No.   12.     California  Art  Tile  Co.   plant,  Richmond,   Contra  Costa  County. 
(From  State  Mineralogist's  Report  XXIII,  p.   7,   1927.) 

in  several  of  the  formations  that  are  widespread  throughout  the  area, 
and  a  number  of  brick  and  hollow-tile  plants  have  been  established  at 
various  places. 

No  deposits  of  high-gi*ade  clays  have  thus  far  been  discovered  in  the 
county,  but  on  account  of  favorable  manufacturing  and  marketing  con- 
ditions, a  number  of  important  ceramic  ])lants  have  been  established  in 
or  near  Richmond,  and  a  wide  diversity  of  ceramic  ware  is  produced. 

California  Art  Tile  Coinparni.  J.  W.  Hislop,  ]3resident ;  L.  J.  Hislop, 
secretary;  W.  A.  Hislop,  chemist;  and  C.  E.  Cummings,  superintendent. 
Address,  Box  1116,  Richmond.  This  plant  is  at  Twentj^-seventh  and 
Maine  streets,  Richmond,  and  was  built  in  1926  to  replace  a  smaller 
plant  that  had  been  established  in  1922.  Decorative  wall  and  mantel 
tile  are  made  from  a  buff-burning  fireclay  body,  and  terra  cotta  glazes. 
Lincoln  clay  and  lone  sand  are  used  for  the  body.  A  view  of  the  plant 
is  shown  on  Photo  No.  12, 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  73 

The  body  mix  is  ])repared  by  grinding  in  a  10-ft.  dry  pan,  followed 
by  a  pug-mill.  A  tile  auger  with  a  patented  cutter  is  used  for  making 
the  regular  sliapes.  and  special  shapes  are  hand  pressed.  Drying  is 
done  in  a  room  heated  by  kiln  gases.  The  glazes  are  applied  by  spray- 
ing before  firing.     Saggers  are  made  at  the  plant  in  a  sagger  press. 

The  kiln  equipment  consists  of  three  30-ft.  and  one  24:-ft.  oil-fired, 
round  down-draft  kihis.  The  tile  are  fired  to  cone  8  to  10  in  four  days. 
The  cooling  time  is  also  four  days. 

Forty  men  are  employed  at  the  plant.  The  rated  output  of  the 
plant  is  40,000  sq.  ft.  of  tile  per  month. 

Bibl:  State  Mineralogist's  Report  XXIII,  p.  7,  1927. 

N.  Clark  and  Som.  At  0x1  ey  siding,  on  the  Southern  Pacific  Rail- 
road, i  mile  north  of  Walnut  Creek,  is  a  shale  pit  owned  by  N.  Clark 
and  Sons.  116  Natoma  Street,  San  Francisco.  The  material  is  a  thin- 
bedded,  soft,  nearly  white,  calcareous  shale  of  Tertiary  age  (Miocene?), 
overlain  unconformably  by  sand  and  gravel.  It  is  used  as  a  component 
of  terra  cotta  and  other  mixtures  in  the  company's  plant  in  Alameda. 

The  deposit  is  Avorked  by  an  open  cut  along  a  face  that  is  approxi- 
mately 200  feet  long.  At  the  southern  end  of  the  pit,  the  shale  bank  is 
70  to  80  feet  high  above  the  floor  of  the  pit,  but  the  contact  between  the 
shale  and  tlie  overlying  gravel  and  sand  dips  toward  the  north,  so  that 
tlie  shale  disappears  at  the  northern  end  of  the  pit.  The  shale  is  broken 
by  hand  drilling  and  blasting,  and  is  delivered  to  a  loading  platform 
eitlier  by  wheelbarrows  or  by  horse-drawn  scraper.  A  storage  shed 
is  provided  for  the  winter  supply  when  mining  is  stopped.  Sample 
Xo.  200  was  taken  for  testing,  tlie  results  of  which  are  on  ]iage  342. 

]Mr.  Faber  of  Walnut  Creek  is  mining  under  contract,  and  two  or 
tliree  men  are  employed  during  the  operating  season.  About  two  cars 
])er  week  are  shipped. 

Bibl :  Cal.  State  Mining  Bur.  Prel.  Rept.  No.  7,  pp.  44-46 ;  State 
Mineralogist's  Reports  XVII,  p.  49,  and  XXIII,  p.  13. 

Mastercraft  Tile  and  Roofing  Compan]i.  (Entire  description  by 
Laizure,  op.  cit.,  p.  7.)  C.  V.  and  F.  A.  Mero,  owners.  Office,  No.  1 
Twentieth  Street,  Riclimond.  Cement  roofing  tile  has  been  manufac- 
tured by  this  company  for  the  past  four  years  at  its  Richmond  plant. 
During  the  pa.st  year  (1926)  hand-molded  clay  roofing  tile  has  been 
added  to  their  line.  The  clay  tile  plant  is  on  San  Pablo  Canyon  road, 
near  San  Pablo,  but  tlie  clay  is  obtained  near  Richmond.  Firing  is 
(lone  in  a  rectangular  down-draft  kiln  using  oil  for  fuel.  Six  men  are 
employed. 

Port  Costa  Brick  Co.  C.  B.  Berg,  president ;  W.  S.  Hoyt,  secretary ; 
B.  F.  Ferrario,  plant  superintendent.  General  offices,  808  Sharon 
Building,  San  Francisco.  The  plant  is  located  three-quarters  of  a  mile 
east  of  Port  Costa,  at  the  edge  of  Carquinez  Straits.  The  products  are 
common  brick  and  hollow  tile. 

A  bank  of  interbedded  bluish  shale  and  red  clay  of  Cretaceous  (?) 
age  is  mined  by  a  14-yard  electric  shovel  in  a  large  open  cut  1000  feet 
from  the  plant.  The  clay  is  transported  to  the  plant  in  5f-5^ard  hopper- 
bottom  side-dump  cars,  hauled  by  a  gasoline  tractor  fitted  with  flanged 
wheels,  or  by  an  electric  third-rail  locomotive.     The  local  material  is 


74  ■  DIVISION  OF    MINES  AND   MINING 

used  alone  for  the  manufacture  of  brick,  but  is  mixed  with  one  part  of 
Lincohi  No.  8  (sample  No.  148,  p.  336)  clay  for  each  two  i)arts  of  local 
clay  for  the  manufacture  of  hollow  tile.  The  Lincoln  clay  is  necessary 
to  secure  sufficient  die  lubrication  to  prevent  lamination  and  rupture 
to  the  clay  as  it  passes  from  the  auger  machine.  A  sample  of  the  local 
clay  was  taken  for  testing.    See  sample  No.  199,  i)a<re  326. 

The  clays  are  prepared  by  grinding  in  two  No.  3  Williams  pulverizers 
and  three  9-ft.  American  dry  pans.  Revolving  screens  are  used  to 
remove  rock  inclusions.  The  pulverized  clay  is  elevated  to  bins  from 
which  it  is  fed  to  the  auger  machines.  A  special  Giant  auger  machine 
is  used  for  brick,  and  an  American  No.  290  auger  is  used  for  tile.  The 
brick  auger  is  equipped  with  a  Freese  cutter,  and  the  tile  auger  has  a 
Chambers  No.  5C  rotary  tile  cutter. 

In  the  summer,  some  ware  is  dried  in  air  under  sheds.  The  drier 
yard  has  a  capacity  of  1,000,000  brick,  and  drying  is  completed  in  12  to 
14  days.  This  method  is  not  used  in  the  winter,  when  all  ware  is  dried 
in  a  22-tunnel  oil-fired  drier.  The  drier  has  a  capacity  of  400  cars  of 
500  brick  each,  or  200,000  brick,  and  the  drj'ing  period  varies  from  four 
to  six  days.  The  dryer  heat  is  supplied  by  an  oil  furnace,  using  Ray 
burners.  Two  25-hp.,  66-in.  fans,  one  of  which  is  used  as  a  pressure 
fan  and  the  other  as  an  exhaust,  force  the  heated  air  through  the  drier. 

Firing  is  done  in  eleven  field  kilns  and  a  Hoffman  continuous  kiln. 
The  Hoffman  kiln  has  22  chambers,  and  has  a  total  capacity  of  400,000 
brick.  The  monthly  output  of  the  kibi  varies  from  1,000,000  to 
1.250,000  brick,  wliieli  corresponds  to  a  firing  cycle  of  15  to  18  days,  of 
which  time  85  to  100  hours  is  occupied  by  firing,  following  the  water- 
smoking  period.  Petroleum  coke  or  coal  screenings  are  used  for  fuel. 
As  a  rule,  the  Hoffman  kiln  is  set  to  a  height  of  three  or  four  feet  from 
the  bottom  with  brick,  and  then  filled  with  hollow  tile. 

Both  hollow  tile  and  brick  are  fired  in  the  field  kilns.  Tlie  local  clay 
is  tender  during  the  water-smoking  period,  and  coal  firing  is  used 
during  this  stage,  followed  by  oil  during  the  actual  firing  period.  The 
oil  is  atomized  with  steam,  Avhich  is  generated  in  a  125-hp.,  horizontal 
fire-tube  boiler,  equipped  with  a  Johnson  rotary  oil  burner. 

The  usual  firing  temperatures  are  between  1600  and  1750°  F.,  for 
brick  and  1850°  F.  for  hollow  tile. 

The  plant  is  operated  by  electric  power  from  the  lines  of  the  Great 
Western  Power  Co.  There  is  a  connected  load  of  about  900  horsepower, 
but  only  400  is  used  at  present.     Fiftj^  to  sixty  men  are  employed. 

Bibl :  Cal.  State  Min.  Bur.  Prel.  Rept.  No.  7,  p.  45 ;  State  Miner- 
alogist's  Reports  XVII,  p.  50,  and  XXIII,  p.  8. 

Richmond  Pressed  Brick  Company.  (Described  by  Laizure,^  supple- 
mented by  notes  by  the  author.)  The  plant  was  erected  by  the  Los 
Angeles  Pressed  Brick  Company,  but  it  became  an  independent  com- 
T)any,  affiliated  with  the  United  Materials  Company,  in  1921.  S. 
W.  Smith,  president ;  W.  S.  Hoyt,  secretary ;  F.  ]\I.  Irving,  plant  super- 
intendent. Home  office,  Sharon  Building,  San  Francisco.  The  plant 
is  at  Point  Richmond,  near  the  Santa  Fe-San  Francisco  ferry  terminal, 
and  is  served  by  a  spur  track  of  the  Santa  Fe  Railroad.     See  Photo 

'  Laizure,  C.  McK.,  Contra  Costa  County,  State  Mineralogist's  Rept.  XXIII,  p.  8, 
1927. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


75 


No.  13.  The  output  includes  pressed  brick,  fire  brick,  face  brick,  pav- 
ing brick  and  red  floor  tile. 

For  the  buff  and  other  li-xht-colored  brick  a  portion  of  the  raw 
materials  used  include  clay  and  sand  shipped  in  from  lone  and  Lincoln, 
as  well  as  some  sand  from  Antioch.  Clay  shale  from  the  pit  adjoining 
the  plant  is  used  for  making  dark-red  brick.  As  the  bank  is  high,  the 
material,  after  blasting,  drops  largelj^  by  gravity  to  a  loading  bin. 
From  here  it  is  trammed  a  short  distance  in  cars  to  the  plant. 

Fire  brick  and  most  grades  of  face  brick  are  made  by  the  stiff-mud 
process.  Dry  pans  and  a  pug-mill  are  used  to  prepare  the  clay  for  the 
auger  machine,  which  has  a  capacity  of  100,000  brick  per  day.  All  of 
the  fire  brick,  and  certain  grades  of  face  brick  are  repressed  before 
passing  to  the  waste-heat  tunnel  driers.  A  specialty  of  the  plant  is  red 
pressed  brick,  which  is  shaped  ))>  di-y  i)ressing,  following  dry-pan 
preparation  of  the  clays. 


Photo  Ko.  13.  Richmond  I'lessed  Urick  Co.  plant,  with  clay  pit  in  background, 
Richmond,  Contra  Costa  County.  (Sample  No.  11 'J.)  (From  State  Miner- 
alogist's Report  XXITI,  p.   8,   1927.) 


The  firing  equipment  consists  of  six  36-ft.  round  down-draft  kilns, 
using  oil,  atomized  by  compressed  air.  The  red-burned  ware  is  fired 
for  nine  days  to  finishing  temperatures  corresponding  to  cones  09  to  07 
(930°  to  975°  C),  and  the  buff  face  brick  and  fire  brick  are  fired  to 
cones  7  to  9  (1210°  to  1250°  C.)  in  seven  days.  The  kilns  are  equipped 
with  pyrometers. 

Electric  power  is  used  to  operate  the  plant.  Fifty-five  men  are 
employed.     See  sample  No.  119,  page  325. 

Standard  Sanitary  Manufacturing  Company.  The  Standard  Sani- 
tary Manufacturing  Company  of  Pittsburgh,  Pennsylvania,  purchased 
the  plants  of  the  Pacific  Sanitary  ^Manufacturing  Company  in  1926,  and 
have  since  constructed  a  new  sanitary  porcelain  plant,  known  as  Pacific 
Pottery,  to  replace  two  smaller  plants  formerly  operated  by  the  Pacific 
company.      The  Standard  company  is  also  continuing  the  operation  of 


76  DIVISION   OF   MINES  AND   MINING 

the  enameling  plant,  now  known  as  the  Pacific  Enamel  Works,  formerly 
owned  by  the  Pacific  company.  These  plants  are  in  Richmond  and  San 
Pablo.     F.  A.  Kales,  Box  W,  Richmond,  is  general  manager. 

The  two  plants  manufacture  a  complete  line  of  porcelain  and  enameled 
sanitary  ware,  except  porcelain  bath  tubs.  Both  plants  are  modern  in 
every  respect,  and  are  designed  for  economy  of  production  and  close 
control  of  manufacturing  methods  to  ensure  uniformity  of  quality. 
Two  tunnel  kilns  were  installed  in  the  new  porcelain  ])lant. 

It  is  against  the  policy  of  the  company  to  permit  ])ublicati()n  of 
details  regarding  the  plant  equipment  and  operation. 

Bibl :  State  Min.  Bur.  Prel.  Rept.  7,  p.  44,  1920. 

Extinct  Companies. 

Among  the  former  brick  companies  that  have  ceased  operations  in 
the  county  are : 

Mt.  Diablo  Pottery  and  Paving  Brick  Co. 

Carquinez  Brick  and  Tile  Co. 

Coast  Firebrick  Co. 

Holland  Sandstone  Brick  Co. 

Diamond  Brick  Co. 

Golden  Gate  Sandstone  Brick  Co. 

Richmond  Brick  Co. 

Gerlack  Brick  Co. 

DEL   NORTE  COUNTY. 
General  Features. 

Del  Norte  County,  in  the  northwest  corner  of  the  state,  is  without 
rail  connections,  and  is  dependent  upon  light-draft  vessels  docking  at 
Crescent  City,  auto  stages,  trucks,  wagon  and  pack  trains  for  trans- 
portation. Lumbering  is  the  principal  industry.  ITnder  such  condi- 
tions, and  with  a  population  of  less  than  3000  (1920  census),  the 
demand  for  clay  products  is  so  small  that  practically  no  clay  industry 
has  been  developed,  and  no  deposits  of  high-grade  clay  have  yet  been 
found  that  will  warrant  mining  and  shipment  to  outside  points. 

The  geology  and  the  physiographic  features  of  the  county  have  been 
well  summarized  by  Laizure  :  ^ 

"A  low  costal  plain,  three  to  five  miles  in  width,  extends  from  the  vicinity  of  Smith 
River  to  a  point  a  few  miles  south  of  Crescent  City.  East  of  and  surrounding  this 
area  of  Quaternary  formations  and  extending-  from  the  Oregon  line  through  Del  Norte 
and  south  into  Humboldt  is  a  belt  of  Franciscan  rocks,  mainly  sandstones  and  shales. 
The  eastern  boundary  of  this  belt  crosses  Smith  River  just  west  of  South  Fork,  and 
its  contact  with  the  succeeding  zone  of  metamorphic  and  eruptive  rocks  marks  the 
line  between  the  Coast  Range  and  the  Klamath  Mountains.  This  succeeding  zone  of 
metamorphics  also  extends  through  the  county  from  north  to  south,  widening  out 
toward  the  north,  where  its  width  is  about  15  miles.  It  is  composed  mainly  of 
serpentine  with  unaltered  masses  of  peridotite  and  many  inclusions  of  'diorite,'  more 
or  less  altered.  This  belt  is  mineralized  and  most  of  the  deposits  of  gold,  copper, 
chromite,  and  platinum  are  associated  v\ith  it.  Between  here  and  the  eastern  bound- 
ary there  is  another  narrow  belt  made  up  largely  of  Franciscan  schist  and  slate, 
intruded  by  deep-seated  igneous  and  volcanic  rocks.  Serpentine  again  predominates 
along  the  boundary  and  extends  over  into  western  Siskiyou  County." 

Clay    Resources. 

Deposits  of  common  clay  suitable  for  brick  manufacture  occur  at 
several  points  within  a  short  distance  of  Crescent  City,  especially  in 

^Laizure,  C.  McK.,  Del  Norte  County:  State  Mineralogist's  Report  XXI,  p.  282, 
July,  1925. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  77 

Elk  Valley  and  along  the  Smith  River.  A  small  brick  yard,  ^vitll  a 
wood-tired  kiln,  was  at  one  time  ojx'rated  by  licnjmnin  llowbind,  wlio 
used  clay  from  the  ]Musiek  i)roperty.  in  P]lk  Valley,  4.8  miles  from 
Crescent  City.'  There  is  said  to  l)e  a  deposit  of  good  pottery  clay  in 
Elk  Valley,-  hut  this  could  not  be  verified  in  the  course  of  the  present 
investigation. 

Musick  Properixj.  This  proi)efty  lies  ().:{  nule  north  of  the  Elk 
Valley  road,  from  a  point  4.5  miles  from  the  center  of  Crescent  City. 
The  pit,  now  abandoned,  is  25  feet  in  diameter,  and  three  to  four  feet 
deep.  A  laj-er  of  black  soil,  less  than  one  foot  deep,  overlies  a  yellow 
plastic  clay,  of  unknown  thickness  and  lateral  extent. 

Sample  No.  180  was  taken  from  this  deposit.  The  test  results  are 
on  page  '-Vl^. 

FRESNO   COUNTY. 
General    Features.' 

Fresno  is  one  of  the  southern  counties  of  the  San  Joaquin  Valley. 
Madera  and  Pierced  counties  are  on  the  north,  Mono  and  Inyo  on  the 
east,  Tulare  and  Kings  on  the  south,  and  San  Benito,  Monterey  and  San 
Luis  Obispo  on  the  west.  The  area  of  the  county  is  5977  square  miles, 
or  nearly  three  times  that  of  the  State  of  Delaware.  The  population 
is  128,779  (1920  census).  The  San  Joaquin  River  separates  Fresno 
from  ]\Iadera  County,  and  the  eastern  boundary  runs  along  the  summit 
of  the  Sierra  Nevada  Mountains.  Along  this  line  are  nnmemus  peaks 
exceeding  1:^,000  feet  in  elevation  above  sea  level. 

Adequate  transportation  is  provided  throughout  the  populous  sec- 
tion of  the  county  by  two  railroads — the  Southern  Pacific  and  the  Santa 
Fe — each  of  which  has  many  branches  to  important  points.  Power  and 
water  facilities  are  well  provided  for  mining,  industrial,  and  agricul- 
tural i)urposes. 

The  ])rincipal  wealth  of  the  county  is  in  agricultural  products,  and 
the  greater  i)art  of  that  portion  of  the  county  lying  in  the  San  Joaquin 
Valley  is  under  cultivation.  The  most  important  mineral  i)roduct  is 
petroleum,  the  bulk  of  which  is  produced  from  the  Coalinga  field,  and 
is  responsible  for  placing  Fresno  County  sixth  in  importance  as  a 
mineral  i)roducer  among  the  counties  of  California.  Miscellaneous 
stone  is  of  secondary  importance.  Other  commercial  products  are  nat- 
ural gas,  granite,  brick  and  hollow  tile,  gold  and  silver,  and  mineral 
water.  Comparatively  little  mineral  development  has  been  done  in  the 
mountainous  portion  of  the  county,  but  occurrences  of  many  useful 
minerals  other  than  those  noted  above  are  known,  among  which  are 
asbestos,  barytes,  chromite,  copper,  gems,  graphite,  gypsum,  limestone, 
magnesite,  marble,  quicksilver,  and  tungsten. 

Clay    Resources. 

No  commercial  deposits  of  high-grade  clays  have  been  discovered  in 
the  county.  The  alluvial  silts  of  the  San  Joaquin  Valley  have  been 
utilized  for  numy  years  for  the  manufacture  of  common  brick  and 
hollow  tile.  There  is,  however,  a  scarcity  of  common  clay  of  suitable 
plasticity  for  this  purpose,  and  it  has  often  been  necessary  to  ship  in 

'  State   Mineralogist's   Report  XIV,   p.    379,    1913-14. 

-  Idem. 

=  See   State   Mineralogist's   Rept.   XIV,   pp.    429-432,    1914. 


78  DIVISION   OF   MINES  AND   MINING 

small  (|iiantities  of  this  material  to  the  brick  yards  from  distant  points. 
Two  brick  plants  are  at  present  (1927)  in  operation,  one  of  which  makes 
hollow  tile  and  face  brick  in  addition  to  common  brick. 

Craycroft-HcroJd  Brick  Co.  F.  J.  Craycroft,  president,  407  GrifSth- 
McKnig"ht  Building-,  Fresno;  Wm.  Turner,  vice  president  and  superin- 
tendent. The  plant  is  located  at  Crayold  siding  three  miles  west  of 
Fresno.  The  products  are  common  brick,  ruffled  and  plain  face  brick, 
and  hollow  tile. 

Some  of  the  clay  used  in  the  plant  is  from  a  superficial  valley  deposit 
of  plastic  clay  6  miles  south  of  Merced.  The  deposit  is  mined  to  a 
depth  of  14  feet,  and  one  car  (50  tons)  per  day  is  used  to  mix  with  a 
local  clay  from  a  pit  near  the  plant.  The  local  clay  is  mined  to  a  depth 
of  five  feet  with  a  horse  scraper.  It  is  a  valley  silt,  with  insufficient 
plasticity  to  be  used  alone. 

The  plant  is  equipped  with  a  9-ft.  dry  i)an  and  revolving  screen  for 
preparing  the  tile  mixture,  and  a  No.  4  Williams  pulverizer  for  the 
brick  mixture.  The  ground  mixture  is  elevated  to  bins  from  which  it 
is  fed  to  the  pug-mills  by  automatic  feeders.  An  American  No.  2  auger 
is  used  foi"  tile,  and  an  American  No.  4  auger  with  a  Freese  cutter 
shapes  the  brick.  Drying  is  generally  under  sheds,  as  under  the  pre- 
vailing conditions  the  waste  heat  drier  with  which  the  plant  is  equipped 
has  insuf^cient  capacity,  and  o]ierating  costs  are  higher  than  open-air 
drying.  In  the  summer,  when  the  atmosphere  is  hot  and  dry,  the  ware 
is  dried  in  about  seven  days. 

The  face  brick  are  fired  in  three  38-ft.  round  down-draft  kilns. 
Common  brick  and  hollow  tile  are  fired  in  field  kilns,  having  a  capacity 
of  950,000  common  brick  each.  The  fuel  is  oil,  atomized  wuth  steam. 
The  firing  period  is  7  days,  to  a  temperature  of  1900°  F.,  followed  by 
7  days  cooling.  Pja-ometers  are  used  to  control  the  temperature  of 
the  down-draft  kilns. 

The  capacity  of  the  plant  is  56,000  brick  and  6,000  hollow  tile  per 
day.     Electric  power  is  used  throughout  the  plant. 

Bibl:  State  Mineralogist's  Report  XIV,  pp.  433-434;  Bull.  38, 
p.  242. 

Pioneer  BricTc  and  Tile  Company.  T.  W.  Hasty,  president  and 
manager;  Arthur  Bentley,  superintendent.  Address  P.  0.  Box  614, 
Fresno.  The  plant  is  at  California  and  Peach  avenues,  south  of  Fresno. 
Common  red  brick  is  the  only  product. 

A  local  valley  clay  is  used,  and  it  is  mined  to  a  depth  of  five  feet  with 
a  Bay  City  gasoline  shovel.  Hardpan  underlies  the  clay.  The  clay  is 
delivered  to  a  Potts  disintegrator,  from  which  it  is  carried  by  a  belt 
conveyer  to  a  pug-mill,  followed  by  a  Bonnett  auger,  equipped  with  a 
Freese  cutter.  The  brick  are  dried  in  sheds,  requiring  from  seven  to 
ten  days.  Three  open  kilns  are  in  use,  fired  with  oil,  atomized  with 
steam.  The  kilns  have  a  capacity  of  1,060,000  brick  each.  The  firing 
period  is  5^  to  6  days,  to  a  maximum  temperature  of  1550  to  1600°  F., 
and  cooling  requires  4  to  5  days.  One  and  one-half  barrels  of  oil  are 
used  per  thousand  brick. 

The  capacity  of  the  plant  is  40,000  brick  per  day.  Electric  power  is 
used  for  all  machinery. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  t)f 

GLENN    COUNTY. 
General    Features. 

Glenn  County  lies  on  the  west  side  of  Sacramento  Valley,  north  of 
Colusa,  and  south  of  Tehama.  Its  area  is  1259  scpiare  miles,  and  the 
population  is  11,8;53  (1920  census).  Willows  is  the  i)rincipal  town. 
The  western  portion  of  the  county  is  in  the  foothills  of  the  Coast  Range, 
and  the  eastern  portion  is  in  the  basin  of  Sacramento  Valley.  In  tlie 
foothills,  deposits  of  chromite,  coi)per,  mang-anese,  sandstone,  and  soap- 
stone  have  been  found.  The  only  couuucrcial  mineral  production  in 
recent  j^ears  is  of  sand  and  lii-avel. 

Clay  Deposits. 

Brick  clays  are  abundant,  especially  in  T.  19  and  22,  R.  8  W.,  M.  D.  M. 
The  clays  are  chiefly  sandy  loam.  No  brick  have  been  made  since  about 
1895,  but  several  yards  Avere  operated  near  Willows  previous  to  that 
time. 

Bibl :  State  Min.  Bur.  Bull.  38,  p.  243. 


HUMBOLDT  COUNTY. 
General    Features. 

Humboldt  County,  of  which  Eureka  is  the  county  seat  and  principal 
town,  is  on  the  north  coast,  between  Del  Norte  and  Mendocino  counties. 
Althoup^h  the  harbor  facilities  at  Eureka  are  excellent,  the  progress  of 
the  county  was  slow  completed  through  to  Eureka  from  the  south. 

The  greater  part  of  the  country  is  rugged  and  mountainous.  The 
ridges  and  spurs  of  the  Coast  Range  traverse  the  county  in  a  north- 
westerly direction,  roughly  paralleling  the  coast  line.  The  coastal  plain 
is  narrow  and  along  the  greater  part  of  the  coast  line  is  practically 
nonexistent. 

The  area  of  the  county  is  1259  square  miles  and  its  i)opulation  is 
11,853   (1920  census). 

Geology. 

The  geology  of  the  county  has  been  summarized  by  Laizure^  as 
follows : 

"Sedimentary  formations  extend  from  the  Mendocino  County  line  north  along  the 
coast  to  a  point  about  five  miles  north  of  Areata.  They  cover  a  strip  about  12  miles 
wide  at  the  south  end.  "Where  the  belt  crosses  the  Humboldt  Base  Line,  the  forma- 
tions have  a  width  of  30  miles,  gradually  running  out  to  a  point  at  the  north.  In  the 
southern  part  the  rocks  consist  of  massive  marine  sandstones,  with  some  shale  and 
limestone  beds,  all  of  Cretaceous  ago.  The  northern  part  is  composed  of  clay  shales 
and  sandstone  of  Tertiary  age,  with  small  areas  of  Quaternary  sands,  gravels  and 
clays,  notably  along  the  lower  reaches  of  Eel  Ri%-er.  The  eastern  boundary  of  these 
sediments  runs  a  little  west  of  north.  The  contact  on  the  east  and  covering  all  the 
southeastern  portion  of  the  county,  and  extending  northwest  to  Rocky  Point  above 
Trinidad  there  is  a  belt  of  Franciscan  sandstone,  chert,  and  serpentine,  about  12  miles 
in  width.  A  long,  narrow  strip  of  Cretaceous  shales,  with  lenses  of  sandstone  three 
to  four  miles  wide,  borders  the  Franciscan  on  the  east.  It  enters  the  county  on  the 
southeast  at  Humboldt  Base  Line,  trends  northwest  and  passes  out  at  Stone  Lagoon, 
near  Orick. 

"All  that  portion  of  the  county  lying  north  and  east  of  this  belt  is  composed  of 
Jurassic,  Paleozoic,  and  pre-Cambrian  metamorphic  and  intrusive  rocks,  including 
limestones,  schists,  slates,  extensive  masses  of  serpentine,  diorite  and  other  crystalline 
rocks.     Most  of  the  gold  and  copper  deposits  occur  in  this  area." 


•  Laizure,    C.    McK.,   Humboldt    Countv :   State   Mineralogist's   Report   XXI,    p.    29.5, 
July,  1925. 


80  DIVISION   OF    MINES  AND   MINING 

Clay    Resources. 

Common  clay  suital)l<'  for  the  maiuifricturc  of  i'e(l-biirnin<i'  struc- 
tural ware  occurs  in  sufficient  (luantity  for  the  needs  of  the  county 
in  the  Quaternar}'  sediments  alonp;  the  coastal  i)lain  and  main  streams. 
Some  of  the  Tertiary  formations  also  contain  common  clay  of  good 
quality.  Four  brick  yards  liave  been  operated  in  the  county  at  various 
times  in  the  past,  one  at  Fortuna,  formerly  owned  by  J.  D.  Thompson,' 
and  three  in  Eureka,  known  as  the  Humboldt  Clay  Manufacturing  Co., 
the  Tracy  Brickyard,  and  the  Eureka  Brick  and  Tile  Co.  Of  these, 
only  the  last  remains  in  operation,  under  the  name  of  the  Thompson 
Brick  Co. 

Pottery  clay  has  been  reported  in  various  localities,  but  none  of 
these  have  yet  proved  to  be  of  economic  importance.  A  salmon  and 
pink-burning  clay  suitable  for  making  earthernware  pottery  by  the 
easting  process  has  been  found  on  the  Angel  Ranch,  18  miles  from 
Areata,  and  a  few  tons  per  year  are  used  in  the  ceramic  art  department 
of  the  Humboldt  State  Teachers  College.  No  white-burning  clays  nor 
fire  clays  have  been  reported  from  the  county.  None  of  the  localities 
Avere  visited  where  'pottery'  clays  have  been  reported,  as  the  known 
(|uality  of  the  clay  was  not  sufficient  to  be  of  economic  value  when  the 
length  of  haul  to  possible  points  of  use  was  considered. 

Angel  Ranch  Clay.  Through  the  courtesy  of  Mr.  R.  H.  Jenkins  of 
the  Humboldt  State  Teachers  College  at  Areata,  who  has  worked  with 
a  number  of  Humboldt  County  clays,  a  sample  of  pink  or  buff-burning 
pottery  clay  from  the  Angel  Ranch  was  secured.  The  Angel  Ranch 
is  near  Hungry  Hollow,  on  the  county  road  to  Hoopaw,  and  the 
deposit  is  about  18  miles  from  Areata,  over  a  fair  road.  On  account  of 
the  fact  that  the  clay  is  not  of  sufficiently  high  quality  to  warrant 
commercial  exploitation  from  a  deposit  at  such  a  distance  from  cheap 
transportation,  the  locality  was  not  visited,  and  little  information  was 
obtained  regarding  the  extent  of  the  deposit.  See  sample  No.  181, 
page  336. 

Freshivater  Slough  Beposii.  South  of  Freshwater  Slough,  near  the 
northeast  corner  of  Sec.  36,  T.  5  N.,  R.  1  W.,  H.  j\I.  is  an  exposure  of 
grayish  white  plastic  clay  in  a  road  cut.  The  clay  exposure  is  two 
feet  thick  and  60  feet  long,  overlain  by  j-ellowish  sandy  soil,  from 
three  to  ten  feet  thick.  Boring  or  test-pitting  would  be  necessary  in 
order  to  determine  the  extent  of  the  deposit.  The  material  is  suitable 
for  the  manufacture  of  common  brick  or  hollow  tile,  as  shown  by  the 
test  results,  sample  No.  18-1,  page  342. 

Loofhourrow  Deposit.  On  the  property  of  Dr.  T.  L.  Loofbourrow, 
First  National  Bank  Building,  Eureka,  four  miles  south  of  Eureka, 
and  one-quarter  mile  east  of  the  highway  is  a  deposit  of  fine-grained, 
excessively  i)lastie  clay  with  a  bluish-gray  color  when  dry.  The  age 
of  the  clay  is  thought  to  be  Miocene.  The  clay  has  been  prospected 
by  two  narrow  open  cuts,  and  by  numerous  hand-auger  holes.  One 
of  the  cuts  is  50  feet  long  and  the  other,  near  b}^  is  12  feet  long.  They 
expose  the  top  of  the  clay  bed,  which  underlies  from  10  to  15  feet  of 
surface  gravel  and  yellowish  clay.     It  is  stated  that  the  auger  holes 


'  State  Mineralogist's  Report  XIV.  p.  392,  1913-14. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  81 

(lemonst rated  tliat  tlic  cl.iy  lias  an  averap:P  tliickncss  of  22  feet  over 
four  or  five  aeres.     Sec  sample  No.  isr»,  pa^e  .'542. 

Bibl:  State  Mineralogist's  lieport  XXI,  ]).  'M)2,  July,  1925. 

W.  A.  Preston  Property.  "A  bed  of  high-grade  clay  is  found  on  the 
W.  A.  Preston  holdings.  Some  of  this  has  been  used  by  R.  II.  Jenkins, 
of  the  Humboldt  State  Teaehers  College  at  Areata,  in  the  production 
of  i)ottery  and  for  experimental  purposes."^ 

The  Preston  holdings  (W.  A.  Preston,  Box  387,  Areata)  comprise 
KiO  aeres  of  i)atented  land,  the  NE]  of  Sec.  2S,  T.  6  N.,  K  1  E.,  H.  M., 
adjoining  the  townsite  of  Areata.  Mr.  Jenkins  reports-  that  the 
deposit  is  not  of  sufficiently  good  quality  to  warrant  exploitation  at  the 
present  time. 

Strong's  Station.  Mr.  Malcolm  B.  Kildale,  geologist,  submitted  a 
sample  of  bluish-gray  plastic  clay  from  near  Strong's  Station,  on  the 
Van  Duzen  River.  This  wa.s  tested  under  samjJe  No.  211.  See  page 
342.  The  deposit  is  stated  to  be  extensive,  but  it  is  too  far  from  the 
market  to  be  of  value,  as  it  is  only  suitable  for  the  manufacture  of 
common  brick. 

Sunny  Avenue  (Eureka)  Deposit.  On  Sunny  Avenue,  one  block 
south  of  Myrtle  Avenue,  in  north  Eureka,  is  an  exposure  of  gray  plastic 
clay  that  is  typical  of  the  sedimentary  deposits  of  the  vicinity.  The 
exposure  of  clay  that  was  sam])led  is  two  feet  thick,  lying  beneath  a 
thin  covering  of  sandy  soil.  The  full  thickness  of  the  clay  bed  could 
not  be  determined  from  the  exposures,  but  it  is  reasonable  to  expect 
a  minimum  of  ten  feet  over  an  area  of  several  acres,  and  it  is  likely 
that  commercial  deposits  of  similar  material  could  be  found  in  many 
]Jaces  near  Eureka  or  Areata,  if  needed.  The  clay  is  suitable  for  the 
manufacture  of  red  brick  and  building  tile,  as  shown  by  the  test  results, 
sample  No.  183,  page  326. 

Thompson  Bricl"  Company.  J.  D.  Thompson,  president  and  owner, 
]\Iyrtle  and  Harrison  streets,  Eureka.  This  company  was  formerly 
known  as  the  Eureka  Brick  and  Tile  Co.  The  property  is  on  Eureka 
Slough,  1.5  miles  from  Eureka,  and  covers  6.18  acres.  There  is  a 
wharf  at  the  plant.  Coinmon  brick,  drain  tile  and  hollow  building 
tile  are  made  from  surface  clay  that  occurs  on  the  property.  The  drain 
tile  is  made  in  sizes  from  3-in.  to  12-in.  diameter. 

The  clay  is  mined  from  an  open  pit  with  a  Fordson  tractor  and  a 
Fresno  scraper.  The  pit  has  a  maximum  depth  of  12  ft.,  but  good  clay 
is  known  to  extend  to  greater  depths.  The  clay  bed  is  made  up  of 
irregular  streaks  of  yellow,  gray  and  black  clay,  with  a  varying  pro- 
portion of  sand.  It  is  generally  too  plastic  to  be  successfully  used 
alone,  and  is  mixed  in  the  plant  with  a  maximum  of  15%  of  sand.  The 
clay  is  dumped  from  the  scraper  into  a  hopper  and  from  there  it  is 
elevated  to  the  head  of  the  plant  in  cars  drawn  by  a  cable  hoist. 
Sample  No.  182  was  taken  from  the  deposit.     See  page  326. 

In  the  plant,  the  clay  is  passed  through  a  disintegrator,  followed  by 
a  pug-mill  and  a  Brevan  auger  machine  equipped  with  a  wire-cutter. 
The  brick  or  tile  are  air-dried  under  sheds.     In  the  cool,  moist  atmos- 

•State  Mineralogi.st's  Report  XXI,  p.  .^02,  1925. 
=  Private   communication,    Aueu.st,    1026. 
6—54979 


82 


DIVISION   OF   MIXES  AND   MINING 


phere  of  the  locality,  drying?  often  requires  a  period  of  four  weeks,  and 
is  seldom  completed  in  less  than  two  weeks. 

Firiiio-  is  done  in  a  30-ft.  round  down-draft  kiln,  wliich  has  a  capacity 
of  7'), ()()()  brick  or  the  etpiivalent  volnme  of  tile.  Tlie  water  smokin<>' 
is  done  with  wood,  for  a  period  of  To  honrs.  The  burn  is  finished  Avitli 
oil,  atomized  with  steam,  reqniring  75  hours  additional.  The  finishing- 
temperature  is  1850°  F. 

The  machinery  is  operated  by  steam  ])ower.  generated  in  oil-fired 
boilers.  From  five  to  eight  men  are  employed  during  the  season.  The 
capacity  of  the  plant  is  1,000,000  brick  or  its  equivalent  per  year,  and 
the  output  is  usually  about  half  that  amount.  The  selling  price  of 
brick,  f.o.b.  \ard.  is  $20  to  $22  per  thousand.  I'lioto  Xo.  14  is  a  view 
of  the  plant. 

Bibl:  State  Mineralogist's  Report  XXI,  p.  301,  1925;  Prel.  Kept. 
No  7.  p.  46,  1920. 


Photo  Xo.   14.      Plant  (^f  Thomp.son  Brick  Co.,  Eureka,  Cal. 
(Photo  by  C.  McK.  Liaizure,  State  Mineralogist's  Kept.  XXI,  p.  301.) 


Weatherhy  Ranch  Deposit.  "There  is  a  deposit  of  clay  of  unknown 
extent  on  property  of  the  Hanify  Lumber  Company,  four  miles  south 
of  Elk  River,  under  lease  to  Clarence  Weatherhy,  Eel  River,  via  Eureka. 
The  strata  exposed  in  a  cut  on  a  ridge  through  the  property  show  clay 
underlain  with  two  feet  of  fine  volcanic  ash.  Underneath  the  ash  is 
six  feet  of  yellow  clay,  then  two  feet  of  lignite  coal,  with  clay  again 
below  the  coal.  Some  production  of  volcanic  ash  has  been  made,  but 
the  coal  and  clay  liave  not  been  developed.  The  Hanify  Lumber 
Company's  railroad  runs  within  {  mile  of  the  deposit."^ 

'  state  Mineralogist's  Report  XXI,  p.  302,  1925. 


CIjAY  resources  and  CERAl^riC   INDI^STRY  83 

IMPERIAL  COUNTY. 
(  Hy    W.    liiiti.iXf;  TrcKKK,   .Milling;   lOiiKincrr.) ' 

General    Features. 

The  priiieii)al  industries  of  Imperial  County  are  agriculture,  stock 
raising'  and  dairying.  its  mineral  resources  are  vai'ied  and  extensive 
and  the  rajjid  and  continued  growtli  of  the  towns  of  Im})erial  Valley 
and  the  manufacturing  industries  of  tlie  Pacific  coast  have  h»d  to  the 
(U'velopment  of  deposits  of  slnicliiral  and  industrial  materials  llii-ough- 
out  the  county. 

Jm{)erial  County  is  bounded  on  the  east  by  the  state  of  Arizona,  noi'th 
by  Riverside  County,  west  by  San  Diego  County  and  south  by  ]\Iexico. 
Its  area  is  4089  square  miles,  with  a  po])ulation  of  43,388  (1920  census). 
The  county  is  served  by  two  railroads,  the  Southern  Pacific  and  the 
San  Diego  and  Ai-izona,  each  of  which  has  several  branches  to 
important  points.  Two  main  paved  highways  afford  easy  access  to  the 
county  from  the  north.  The  highway  between  San  Diego  and  El  Centro 
forms  ])art  of  the  coast  route  from  Tjos  Angeles  to  Imperial  Valley, 
Yuma  and  Phoenix.  The  other  route  from  Los  Angeles  is  over  the 
Valley  Boulevard  by  way  of  Beaumont  and  Banning  to  Brawley  and 
El  Centro.  The  Blythe-Glamis  route  to  Yuma  and  Imperial  Valley  is 
one  of  the  main  desei-t  roads,  which  enters  the  county  from  the  north- 
east at  Palo  Verde  and  runs  southwest  to  Glamis,  from  which  point  the 
road  follows  the  railroad  north  to  Niland. 

Physiography. 

The  most  important  feature  of  Imperial  County  is  the  broad  and 
nearly  level  expanse  of  the  Colorado  River  delta,  which  separates  the 
Gulf  of  California  from  the  Salton  Basin  and  is  known  as  Imperial 
Valley.  The  Salton  Sea  region  is  one  of  the  interesting  topogra])hicnl 
features  of  the  county.  Diagonally  across  the  region,  from  southeast 
to  northwest,  it  extends  as  a  great  trough  whose  lowest  ])oint  is  nearly 
300  feet  below  sea  level.  On  the  west  side  of  this  deep  trough  rise  the 
Peninsular  Mountains,  whose  culminating  points  are  1 0,000  feet  above 
sea  level.  On  the  east  side  is  a  desert  containing  irreguhir  ranges  and 
undrained  basins  ranging  in  altitude  from  a  few  hundred  feet  to  5000 
feet  or  more. 

The  eastern  border  of  the  territory  is  formed  by  the  Colorado  River, 
whose  waters  flow  through  a  low  valley  and  Anally  spread  out  over  a 
huge  delta  as  they  enter  the  Gulf  of  California. 

The  surface  of  the  central  portion  of  the  Salton  Basin  is  very  even 
and  nearly  flat ;  about  its  borders  are  alluvial  slopes.  In  a  number  of 
l)laces  rocky  masses  protrude  above  the  even  surface  of  the  basin  as 
rocky  islands  project  out  of  the  sea.  Such  island-like  features  are 
formed  by  Borego,  Superstition  and  Carrizo  mountains,  the  Cargo 
]\Iuchacho  iMountains,  Pilot  Knob  and  a  number  of  volcanic  buttes  100 
to  200  feet  high  south  of  Salton  Sea. 

The  Sand  Hills  constitute  an  important  feature  of  the  physiography 
of  Salton  Basin.  The  sand  hills  east  of  Imperial  Valley  constitute  the 
largest  belt  of  dunes  in  this  region  and  also  one  of  the  largest  in  the 
United  States.     They  extend  southeastward  from  the  vicitity  of  Amos 

'  state  Mineralogist's  Report  XXII,  pp.  248-285,  1926.  Such  portions  of  this 
report  were  used,  with  a  few  sHght  alterations,  as  have  a  bearing  on  the  clay 
resources  of  the  county. 


84  DIVISION   OF   MINES  AND   MINING 

and  ttM-iuinate  a  few  miles  beyond  tlie  ^lexican  boundary,  beinji,'  about 
40  miles  in  len<itli  and  fi'om  two  to  six  miles  in  width.  The  crests  of 
some  of  the  dunes  rise  in  places  200  to  800  feet  above  the  hind  on  either 
side. 

Another  interest in<i-  I'ealiire  of  the  Salton  Basin  is  the  old  beach  line 
which  lies  40  to  50  feet  above  sea  level  and  encircles  Imperial  Valley, 
the  Salton  Sea  and  part  of  Coachella  Valley  south  of  Indio. 

Geology. 

The  most  useful  references  on  the  geology  of  the  region  are  Blake's 
original  description  of  the  Salton  Basin/  and  jNIendenhall's  papers  on 
Coachella  Valley  and  Carrizo  Creek,-  Fairbanks'  report,'  and  U.  S. 
Geol.  Survey  Water  Supply  Paper  No.  497,  'The  Salton  Sea  Region, 
California, '  by  John  S.  Brown.  In  the  following  notes  on  the  geology 
of  Imperial  County  excerpts  are  taken  from  the  last-named  paper : 

According  to  most  geologists  who  have  worked  in  this  region,  the 
oldest  rocks  are  probably  of  pre-Cambrian  age.  The  pre-Cambrian 
rocks  occur  mainly  in  the  desert  mountains  in  the  region  between  the 
Salton  Basin  and  the  Colorado  River.  They  are  commonly  flanked  by 
Tertiary  or  later  sediments  about  the  mountain  borders  and  in  large 
areas  they  are  covered  or  intruded  b}'^  Tertiary  volcanic  rocks.  The 
rocks  that  can  most  certainly  be  referred  to  as  the  oldest  series  consist 
of  granite  and  granitic  gneiss.  In  this  series  probably  belong  the 
granite  and  schist  that  compose  most  of  the  Cargo  Muchaco  Range  and 
the  granite,  slate,  and  schist  that  form  the  basements  of  the  Picacho 
Hills  and  the  eastern  part  of  the  Chocolate  Mountains.  On  the  western 
border  of  the  desert  in  Carrizo  Mountain,  and  on  the  top  of  Fish  ]\Ioun- 
tain  in  the  Carrizo  Creek  region,  are  beds  of  marble  and  some  schist 
and  sandstone  which  have  been  referred  by  Mendenhall  and  Fairbanks 
to  the  Paleozoic,  with  suggestion  that  they  may  be  Carboniferous. 
]\Iarble  schist  and  gneiss  of  undetermined  age  in  the  Santa  Rosa  iMoun- 
tains  may  belong  to  the  same  series  of  rocks  as  the  Carrizo  Mountain 
district. 

Tertiary  Sedimentary  Deposits. 

Sedimentary  beds,  believed  to  be  of  Tertiary  age,  occupy  extensive 
areas  along  the  southwest  and  northeast  sides  of  the  Salton  Basin  and 
presumably  underlie  practically  the  entire  basin.  The  largest  and  best- 
known  exposures  southwest  of  Salton  Sea  are  in  Carrizo  Creek  Valley, 
around  Yuba  Well,  south  of  the  Santa  Rosa  Mountains  and  northeast 
of  Superstition  Mountain  and  Borego  Mountain,  and  on  the  north  side 
of  Fish  Mountain.  The  Tertiary  beds  consist  of  soft,  poorly  consoli- 
dated conglomerates,  sand  and  clay  containing  in  places  a  large  amount 
of  gypsum  and  some  other  saline  materials.  Part  of  the  Tertiary  beds 
in  the  region  are  marine  and  part  terrestrial. 

Tertiary  and  Quaternary  Volcanic  Rocks. 

The  volcanic  rocks  of  this  area  are  probably'  mostly  Tertiarj^ ;  some 
of  them  are  Quaternary.  They  occur  as  flows  interbedded  with  sedi- 
mentary beds  in  the  Carrizo  region,  around  Superstition  ]\Iountain,  and 
in  Iris  Pass.     The  lavas  are  most  prorhinent  in  the  Chocolate  and  Palo 

>  Blake,  TV.  P.,  Pacific  Railroad  Reports,  Vol.  V.  1853. 

=  Mendenhall,  W.  C,  Ground  waters  of  the  Indio  Region,  Calif.,  with  a  sketch  of 
the  Colorado  Desert:  U.   S.  Geol.   Surv..  Water  Supply  Paper  No.   225,   1909. 

'  Fairbanks,  Harold  W..  Geologv  of  San  Diego,  Orange  and  San  Bernardino  Coun- 
ties:  State  Mineralogist's  Report  XI,  pp.  76-120,  1892. 


CLAY  RESOURCES  AND  CEKA:MIC  IXUUSTKY  85 

Verde  mountains.  The  Palo  Verde  Mountains  are  entirely  volcanic, 
bein<r  chiefly  a  nuiss  of  andesitic  or  rhyolitic  flows.  The  Chocolate 
Mountains,  from  one  end  to  the  other,  exhibit  a  great  mixtui-e  of  ande- 
sitic and  rhyolitic  flows  with  possibly  syenite  and  trachyte  in  the 
west  end. 

The  only  volcanic  material  of  un(iuestionably  Quaternary  ap:e  in  this 
re*rion  is  found  in  the  vicinity  of  the  mud  volcanoes  southeast  of  Salton 
Sea,  where  three  or  four  small  buttes  of  black  obsidian  protrude  through 
the  Quaternary  silt. 

Quaternary  Deposits. 

The  Quaternary  deposits  immediately  underlie  nearly  all  the  low- 
lands and  have  the  largest  areal  extent  of  all  the  rock  formations. 
They  underlie  the  larger  ])art  of  the  Salton  Basin  and  practicall.y  all 
of  the  Colorado  River  Valley.  The  valley  fill  consists  of  sand,  gravel 
and  clay  washed  down  from  the  hills  and  mountains. 

Mineral    Resources. 

Imperial  County  ranks  as  the  forty-sixth  county  in  the  state's 
miiu'ral  ])roduction.  It  contains  de])osits  of  clay,  copper,  cyanite,  gold, 
gems,  gypsum,  lead,  manganese,  marble,  mineral  i)aint,  pumice,  salt, 
silver,  sodium,  strontium,  sulphur  and  talc,  largely  undeveloped. 

Clay    Resources. 

Imperial  County  contains  extensive  deposits  of  river  silt  that  has 
been  used  for  the  manufacture  of  common  brick  and  tile. 

Extensive  exposures  of  Tertiary  clays  are  found  on  the  west  margin 
of  Im])erial  Valley  toAvard  Carrizo  Creek.  These  clays  are  many  miles 
in  extent  and  of  great  thickness,  but  have  not  been  prospected  suffi- 
ciently to  determine  their  value  for  commercial  pur])oses.  On  these 
Tertiary  clay  deposits  a  number  of  locations  have  been  made  by  the 
Columbia  Cement  Company,  of  Los  Angeles,  and  the  American  Port- 
land Cement  Company,  of  San  Diego.  Of  special  interest  to  the 
ceramic  industry  is  the  extensive  deposit  of  cyanite  at  Ogilby. 

During  the  develo])inent  of  the  towns  of  Imperial  Valley,  a  numbei- 
of  local  brickyards  have  been  established  and  operated  for  a  short  time. 
The  Simons  Brick  Company,  described  below,  is  the  only  operator  in 
the  county  at  present. 

Full  Moon  Clay  Deposit.  The  deposit  is  located  on  the  southwestern 
slope  of  the  Chocolate  range  of  mountains,  in  T.  10  S.,  R.  16  E.,  S.  B. 
B.  and  M.,  eight  miles  north  of  Iris  siding  on  the  Southern  Pacific 
Railroad. 

Holdings  comprise  five  claims  known  as  the  Full  Moon  group.  Owner, 
J.  Thebo,  of  La  Mesa,  California. 

The  clay  is  a  white  talcose  clay,  showing  a  high  alumnia  content. 
The  development  consists  of  a  number  of  o])en  cuts  along  the  surface 
outcrop.     Analysis  of  clay  made  by  A.  J.  Forget,  of  Los  Angeles: 

Silica     (SiO,)     27.93% 

Alumina    (A1.,0.,)    42.33% 

Iron    (FeoOa)     1-92% 

Lime    (CaO)    0.53% 

Soda    0.70% 

Water    (combined)    12.44% 

Moisture 0.74% 

Sulphur  anhydride  (SOa) 13.39% 

100.00% 


86 


DIVISION   OF   MINES  AND   MINING 


Simons  Brick  Companij.  Walter  R.  Simons,  president.  Main  office, 
125  West  Third  Street,  Los  Angeles.  This  company  is  the  only  manu- 
facturer of  brick  and  tile  in  the  valley  at  the  present  writing  and  only 
operates  the  plant  at  intervals  to  supph^  the  local  demand.  The  brick 
plant  is  located  about  one  mile  southeast  of  El  Centro. 

The  clay  used  is  local  silt  of  the  valley,  which  is  very  fine  and  sticky. 
This  dei)osit  continues  unchanged  to  a  depth  of  1500  feet  as  shown  by 
local  borings,  but  varies  slightly  in  texture  and  the  proportion  of  sand 
present,  the  variations  in  composition  occurring  every  three  or  four 
feet.  This  variation  enables  the  brick  maker  to  mingle  layers  of  differ- 
ent (puililies  and  form  a  brick  mixture  of  suitable  character. 

Tlie  material  from  the  clay  pit  is  delivered  by  scrapers  to  the  hop})er, 
from  which  it  goes  to  a  belt  conveyor,  and  is  elevated  to  a  set  of  rolls. 
The  material  from  rolls  is  elevated  by  bucket  elevator  to  a  screen.  The 
through  size  from  the  screen  goes  to  two  stitf-mud  brick  machines.  The 
brick  and  tile  g(»  to  di'ving  sheds,  then  are  oil  fired  in  open-field  kilns. 


Photo    No.    15.     Vitrclrax    cyanitc    deposit.    Cargo    Muchacho    Range,    near   Ugilby, 
Imperial  County.      Photo  liy  W.  B.  Tuoker  ;  Stale  Mineralogist  Rep.  XXII,  p.  270. 

Cyaxite  and  Dumortierite. 

C\vaiiite  (Al,(),.SiO,)  and  dumortierite  (8AU03.B,0,.6SiO,.n,0) 
are  both  aluminum  silicates  but  with  slightly  different  physical  charac- 
teristics. Cyanite  is  an  aluminum  .silicate  of  the  same  chemical  com- 
])osition  as  andalusite  and  sillimanite.  but  crystallizing  in  the  triclinic 
system ;  occurs  usually  in  long-bladed  crystals  rarely  terminated ;  hard- 
ness, 5-7.25 ;  gravity,  3.56-3.67 ;  color,  blue. 

An  extensive  deposit  of  cyanite  occurs  near  Ogilby,  which  is  being 
develo])ed  by  the  Yitrefrax  Comiiany.  of  TiOs  Angeles. 

Dumortierite  is  a  basic  silicate  of  aluminum,  witli  boron,  but  crystal- 
lizing in  the  orthorhombic  system.  It  occurs  usually  in  small  prisms; 
color,  blue,  dark  blue  and  violet-red;  hardness,  7;  gravitx .  3.22-3.45. 

Dark  blue  boulders  of  dumortierite  have  been  found  in  the  Avashes 
in  the  Pieaeho  district  about  25  miles  from  Ogilby.  These  mt!tamori)hie 
minerals  are  found  in  the  schists  and  gneisses. 


CLAY  RESOURCES  AND  CERA:MIC  IXDUSTRY  87 

0()ilb\j  Cyanite  Deposits.  The  de{)o.sits  of  eyaiiite  occur  near  the 
base  of  hills  on  the  western  slope  of  the  Cargo  Muchaeho  range  of 
inonntains.  three  miles  northeast  of  Ouilby.  Elevation  500  feet.  Hold- 
ings eoiiiprise  ten  claims  known  as  the  Drifted  Snow  and  Blue  Bird 
groups.  200  acres.  Owner,  Vitrefrax  Company,  5100  Pacific  Boule- 
vard, Los  Angeles. 

The  tii'st  diseovery  of  cyanite  was  uuule  in  a  low.  rounded  hill  one- 
eighth  mile  wide  by  one-half  mile  long,  and  jjrobably  consists  of  25  per 
cent  cyanite  in  a  matrix  of  quartz.  One-quarter  of  a  mile  farther  east, 
a  ])rominent  vein  of  cyanite  outcrops  for  one-half  mile  in  length,  at 
the  foot  of  the  Cargo  ^Muchaeho  I'ange.  The  vein,  which  occurs  in  a 
mica  schist,  is  nearly  vertical  and  varies  from  10  to  200  feet  in  width. 
Open  cuts  and  tunnels  have  been  made  along  the  deposit  for  a  distance 
of  over  500  feet  along  the  strike.  The  most  extensive  showing  has 
been  found  on  the  north  end  of  the  deposit.  Here  it  outcrops  for  over 
200  feet  in  width.  Quartz  is  the  gangue  mineral,  while  small  amounts 
of  black  tourmaline  occur  throughout  the  vein  material.  On  the  south 
end  of  the  deposit,  both  walls  of  the  vein  have  a  selvage  of  talc. 

Eight  to  ten  men  are  employed  in  getting  out  material  for  shi])ment 
to  the  company's  plant  at  Los  Angeles,  where  it  is  being  used  in  the 
manufacture  of  high-grade  refractories. 

INYO   COUNTY. 

(.V.y     \V.     BUKI.IXG     TUCKKll.)' 

General    Features. 

Inyo  County  lies  on  the  eastern  border  of  the  state,  north  of  San 
Bernardino  County.  It  is  the  second  lai'gest  county  in  the  state,  with 
an  area  of  10,019  square  miles.  The  population  is  but  7031  (1920 
census).  Within  the  borders  of  the  county  are  both  the  highest  point 
and  the  lowest  ])oint  in  the  United  States.  IMount  Whitney  has  an 
elevation  of  14,501  feet,  and  Salt  Flat,  in  Death  Valley,  is"  280  feet 
below  sea  level. 

In  recent  years  the  county  has  become  more  accessible  with  the  con- 
struction of  several  automobile  highways  which  supplement  the  railway 
lines  that  already  served  important  i)oints. 

Geology. 

The  general  geology  of  the  county  has  been  described  in  detail  in 
Report  XV  of  the  State  Mineralogist,  pp.  45  to  60,  and  a  geologic  ma]) 
accompanies  that  report.  Granitic  rocks  form  the  backbone  of  the 
l)rincipal  mountain  ranges.  Paleozoic  and  Mesozoic  metamorphic 
formations,  ])rineipally  crystalline  limestones,  (juartzites,  and  schists 
are  prominent  in  the  eastern  ])art  of  the  county.  These  have  been 
intruded  by  porphyry  and  diorite,  and  there  have  been  numerous  flows 
of  rh\olite,  andesite,  and  basalt.  Tertiary  sediments  were  deposited  in 
the  Death  Valley  region,  and  saline  deposits  formiMl  from  the  evapora- 
tion of  sea  waters. 

In  the  higher  mountainous  sections  are  found  many  vein-forming 
minei-als,  and  in  the  lake  beds  of  Death  Valley  saline  deposits  exist. 
The  mineral  resources  include  andalusitc,  antimony,  asbestos,  bai-ytes, 

1  Inyo  County,  State  Mineralogist's  Report  XXII,  pp.  45.3-530,  192G.  I'ortions  of 
this  article  were  abstracted  for  use  in  the  present  report. 


88  DIVISION   OP    MINES  AND   MINING 

borates,  copper,  dolomite,  yeins,  gypsuin,  lead,  marble,  uiontmorilloiiite 
('bentonite,'  'shoshonite'  and  'amargosite'),  soda,  sulphur,  talc, 
tungsten,  and  zinc.  The  i)rincipal  products  are  lead,  soda,  borates, 
bentonite,  and  silver. 

Clay    Resources. 

Extensive  beds  of  Tertiary  clay  occur  along  the  Amargosa  River  in 
the  vicinity  of  Shoshone  and  Tecopa.  These  beds  vary  in  thickness 
from  6  to  20  feet  and  in  different  localities  are  covered  with  an  over- 
burden of  volcanic  ash  and  gravel  wash. 

Fairbanks  Clay  Deposit.  R.  J.  Fairbanks,  owner,  Shoshone..  The 
property  is  situated  one  mile  southeast  of  Shoshone,  on  the  west  side 
of  the  Amargosa  River.  The  holdings  comprise  160  acres.  Elevation 
1600  feet. 

The  beds  of  clay  trend  north  and  south  and  are  6  to  8  feet  thick,  over- 
lain by  4  to  6  feet  of  volcanic  ash.  The  clay  is  green  in  color  and  quite 
plastic. 

The  Pacific  Minerals  and  Chemical  Company  and  Gladding,  McBean 
and  Company,  of  San  Francisco  and  Los  Angeles,  also  own  deposits  of 
clay  located  between  Shoshone  and  Zabriskie. 

KERN   COUNTY. 
General    Features.' 

Kern  is  the  southernmost  county  in  the  San  Joaquin  Valley,  and 
takes  in  the  southern  portion  of  the  Sierra  Nevada  ^Mountains,  includes 
a  portion  of  the  Coast  Range  in  its  western  end,  and  to  the  south  and 
east  of  the  Sierras  it  encloses  a  large  section  of  the  ]\Iojave  Desert.  The 
total  area  of  the  county  is  8100  square  miles.  It  is  the  third  largest 
county  in  the  state,  and  is  bounded  on  the  north  by  Tulare,  Kings  and 
Inyo,  on  the  south  by  Los  Angeles  and  Ventura,  on  the  east  by  San 
Bernardino,  and  on  the  w^est  by  San  Luis  Obispo.  It  is  characterized 
by  greater  variety  and  contrasts  of  topography,  geology,  climate,  and 
resources  than  any  other  California  county. 

The  northern  i)art  of  the  county  is  well  provided  witli  water  and 
power  for  industrial,  agricultural  and  mining  purposes.  In  the  south- 
ern part  of  the  county,  on  the  ]\Iojave  Desert,  water  is  relatively  scarce, 
but  power  can  be  secured  for  all  important  purposes  from  the  lines  of 
the  Southern  California  Edison  Company,  now  one  of  the  largest  power 
systems  in  the  world.  Transportation  facilities  are  provided  to  import- 
ant points  in  the  county  by  the  Southern  Pacific  and  Santa  Fe  railroads, 
supplemented  by  a  system  of  state  and  county  highways. 

The  principal  mineral  product  is  petroleum,  the  production  of  wliieh 
maintained  for  many  years  the  supremacy  of  Kern  County  among  all 
counties  of  California  in  the  value  of  its  mineral  output.  Kern  was 
surpassed  by  both  Los  Angeles  and  Orange  counties  in  1923,  but  by 
Los  Angeles  only  since  then,  for  which  petroleum  also  is  responsible. 

Among  the  commercial  mineral  products  of  the  county,  in  addition 
to  petroleum,  are  natural  gas,  borates,  cement,  brick  and  clay,  gold  and 
silver,  salt,  miscellaneous  stone,  and  antimoii.w  Other  minerals  that 
have  been  discovered  or  that  have  been  worked  in  the  i)ast  are:  as])lialt, 

'State  Mineralog-ist's  Report  XIV,  itp.  471-475,   lOH. 


("LAY  RESOURCES  AND  CERAMIC  INDUSTRY  89 

coppei-,  fuller's  eartli,  p:ems,  yypsum,  iron,  Ic.ul.  limestone,  magnesite, 
marble,  mineral  paint,  potash,  soapstone,  soda,  siili)hiir,  and  tungsten. 

Clay    Resources. 

The  alluvial  silt  of  the  San  Joaquin  Valley,  in  the  vicinity  of  Bakers- 
field,  has  been  in  use  for  many  years  for  tlie  manufacture  of  common 
brick.  As  is  the  case  in  Fresno  County,  deposits  of  plastic  common 
clay  are  scarce.  The  local  silts  have  barely  enough  plasticity  to  permit 
the  manufacture  of  a  satisfactory  grade  of  common  brick  by  the  soft- 
mud  process.     Two  brick  plants  are  in  operation  in  Bakersfield. 

A  deposit  of  high-grade  clay  at  Kosainond,  near  Mojave,  has  attracted 
attention  for  many  years.  It  is  possible  that  more  extensive  prospect- 
ing in  the  desert  region  Avill  disclose  other  deposits  of  high-grade  clays. 

Bakersfield  Rock  and  Gravel  Companu.  A.  II.  Kaspe  and  W.  J. 
Walters.  It  is  reported  ^  that  this  company  was  developing  clay  lands 
in  1927,  in  coniiection  with  its  saml  and  gravel  business.  A  conveyor 
system,  storage  bins,  and  loading  equi]>ment  were  to  be  installed,  at  a 
cost  of  $18,000.  Further  details  are  lacking  at  the  time  of  going  to 
press. 

Balicrsfidd  Sandstone  Brick  Compayiy.  James  Curran,  manager. 
Office  and  plant  at  501  Sonora  Street,  Bakersfield.  The  company  owns 
40  acres  of  land. 

Common  red  brick  are  manufactured  from  an  alluvial  silt  which  is 
mined  to  a  depth  of  ten  to  twelve  feet  Avith  a  clam-shell  excavator. 
The  soft-mud  process  is  used.  The  plant  is  equipped  with  a  pug-mill 
and  a  Martin  press.  Drying  is  done  on  steel  trucks,  either  in  the  open, 
or  under  sheds.  As  the  plant  is  only  operated  during  the  dry  season, 
drying  is  usually  completed  in  seven  days.  Firing  is  done  in  field 
kilns,  whieli  are  started  with  gas  and  finished  with  oil,  atomized  with 
steam.  Thermo-electric  pyrometers  are  used  for  recording  tempera- 
tures. At  the  fire-holes,  the  finishing  femj)erature  is  2100°  F.,  two 
feet  above  the  arch  it  is  1840°  F.,  and  two  feet  below  the  top  it  is 
1750°  F. 

The  eajiacity  of  the  i)lant  is  40,000  brick  a  day,  and  14  men  are 
(■iu])l()yed  dui'ing  the  operating  season. 

Bibl :  State  Mineralogist's  Kept.  XIV,  p.  477;  and  Prel.  Kept.  No. 

7,  p.  48. 

Kern  County  Brick  Co.  Owned  by  King  Lumber  Co.,  Elmer  King, 
l)resident,  Bakersfield.  This  property  comprises  12  acres  in  Sec.  21, 
T.  29  S.,  R.  28  E.,  M.  D.  M.,  on  the  eastern  outskirts  of  Bakersfield. 
The  deposit  is  a  sandy  loam  25  feet  thick,  and  has  been  used  for  the 
])roduction  of  common  brick  since  about  1900.  The  soft  mud  process 
is  used,  the  equipment  consisting  of  a  disintegrator,  pug-mill,  and 
6  mold  press.  Cable  haulage  is  used  to  transjiort  the  brick  from  the 
l)resses  to  the  drying  sheds.  Firing  is  done  in  oil-fired  field  kilns. 
The  capacity  of  tlie  plant  is  37,000  brick  per  day,  the  annual  produc- 
tion depending  upon  local  demand.     Ten  men  are  employed. 

Titus  Chn/  Deposit.  H.  E.  Titus  of  Kosamond  owns  two  ])lacer 
claims  totaling  40  acres,  comjirising  the  K\W \  of  the  SE]  of  See.  11, 
T.  9  N.,  R.  1-')  W.,  S.  B.  M.,  covering  a  deposit  of  pottery  clay  of  good 

■  Clay-Workor,    May,   1927,   p.   486. 


90  DIVISION  OF    MINES  AND   MINING 

quality.  Tlie  (listaiice  by  road  i'l'oiu  Ivosaiuond  is  4.8  miles  in  a  direc- 
tion slightly  north  of  due  Avest.  The  clay  has  been  developed  by  an 
open  pit,  and  by  a  200-foot  tunnel,  noAv  inaccessible. 

The  clay  is  enclosed  in  felsite  porphyry,  and  is  apparently  a  local 
alteration  and  docoiiii)Osition  in  ])lace,  of  a  phase  of  this  rock.  Inclu- 
sions of  porphyry  in  various  stages  of  alteration  are  intermingled 
with  the  clay.  The  deposit  has  no  definite  stratification,  but  appears 
to  lie  in  a  nearly  Hal  bed,  overlain  by  a  red-c<)h)i'ed  porphyry  capping. 

Tlie  known  dimensions  of  the  deposit  is  800  feet  wide,  700  feet  long, 
and  50  feet  dee]i,  with  unknown  possibilities  for  extension  in  any  of 
these  dimensions.  The  ])roperty  was  formerly  known  as  the  Hamilton 
deposit.  At  various  times  during  a  period  of  over  10  years,  clay  has 
been  mined  from  an  o]ien  pit,  and  shi])ped  to  ceramic  plants  in  the 
Los  Angeles  district,  notably  the  Los  Angeles  Pottery  Company  and 
the  Pacific  Sewer  Pipe  Company  both  of  whicli  are  now  non-existent 
under  their  original  names  or  ownership,  and  more  recently  to  the 
Tropico  plant  of  Gladding,  ^McRean  &  Co.  Tlie  clay  has  been  used  in 
stoneware  and  sewer-pijie  mixtures,  and  a  commercial  test  run  has  been 
made  for  terra  cotta  mixtures.  It  is  likely  that  the  property  will 
eventually  be  acquired  by  one  of  the  manufacturing  companies,  although 
at  present  develojuuent  work  has  not  progressed  far  enough  to  permit 
a  prediction  as  to  the  probable  tonnage  and  quality  that  can  be  expected 
beyond  the  known  limits  of  present  knowledge.  Sample  Xo.  114  was 
taken  from  this  dei)osit,  and  the  test  results  are  given  on  page  312. 

IT'.  ^'.  Wehh  of  Rosamond  owns  a  ])roperty  one  mile  west  of  the 
Titus  claims,  on  what  is  a  supposed  extension  of  the  same  clay  bed. 
This  property  was  not  visited. 

Merry  Widow  Mine.  Mrs.  ]Mary  Y.  Smith  of  Kosamond  is  the  prin- 
cipal owner  of  the  ]\Ierrv  Widow  mine  comprising  two  lode  claims  in 
the  SWi  of  Sec.  8,  T.  9  5j.,  R.  12  W.,  S.  B.  M.,  2.8  miles  by  road  north 
of  Rosamond,  of  which  1.6  miles  is  on  the  highway  to  ]\Iojave.  This  is 
in  the  Rosamond  gold  mining  district,  uoav  idle,  but  at  one  time  a  small 
jiroducer  of  gold  from  narrow  veins  in  granite  porphyry  and  slate. 
Two  samples  were  taken  from  an  800-foot  tunnel  on  the  ]\Ierry  Widow 
property.  One  of  these,  No.  115,  is  footwall  gouge  from  a  drift  on  a 
vein  encountered  at  a  point  200  feet  from  the  portal  of  the  tunnel. 
The  gouge  is  over  five  feet  in  thickness,  and  lies  at  an  angle  of  45  to  50°, 
dipping  south.  About  40  feet  of  this  material,  measured  along  the 
strike  of  the  vein,  is  exposed  in  the  drift.  The  test  results,  page  349. 
slioAV  that  the  clay  has  little  value  for  ceramic  purposes,  on  account  of 
jioor  plasticity,  red  color,  high  shrinkage,  fire  splitting,  and  low  fusion 
point. 

The  other  sami)l(',  Xo.  116,  was  taken  of  the  decomposed  rock  that 
occurs  near  the  portal  of  the  tunnel.  It  is  evidently  an  altered  granite 
porphyry.  Test  results,  ])age  349,  were  even  less  favorable  than  those 
obtained  on  sample  Xo.  115. 

KINGS  COUNTY. 
General    Features. 

Kings  County  is  in  the  south-central  portion  of  the  state,  soutli  of 
Fresno  County.  Its  ai'ea  is  1559  sfpuire  miles,  and  tlie  po])ulation  is 
22,031   (1920  census).     The  principal  town  is  Ilanford.      The  western 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  01 

edjfe  of  the  county  is  in  the  foothills  of  the  Coast  Range.     The  rest  of 
the  county  is  in  the  basin  of  the  San  Joaquin  Valley. 

The  mineral  resources  of  tlie  county  are  jiractically  undeveloped. 
Dejiosits  of  fuller's  earth,  gypsum,  mineral  paint,  natui'al  gas,  and 
([uit-ksilver  have  been  noted.  The  commercial  production  is  almost 
negligible. 

Clay    Resources. 

Common  brick  clays  are  rcasonabl\'  abuudaut  in  llic  vicinity  of  Han- 
ford  and  elsewhere  in  the  county.  Two  former  brickyards,  the  Clinker 
Brick  Company  and  Trewhitt  Brickyard,  both  near  Ilanford,  were 
abandoned  prior  to  1911. 

Bibl:   State  .Alineralouist's  Kept.  XIV.  p.  527,  1913-14;  State  :\Iin. 
Bur.  Bull.  ;J8,  p.  24:3 ;  Prel.  Kept.  7,  ]).  49. 


LAKE  COUNTY. 
General    Features. 

Lake  is  one  of  the  counties  north  of  San  Francisco  Bay.  It  is 
bounded  on  the  north  by  ^Meiidoeino  aiul  (Tlenn  counties,  on  the  east  by 
Glenn,  Colusa  and  Yolo,  on  the  south  by  Napa,  and  on  the  west  by 
Sonoma  and  Mendocino.  It  has  an  area  of  1328  square  miles,  and  its 
])oj)ulation  is  5542  (1920  census). 

The  outstanding  physiogra])hic  feature  of  tlie  county  is  Clear  Lake, 
which  has  been  a  prominent  resort  area  for  many  years.  Clear  Lake  is 
surrounded  by  rolling  hills  in  which  are  many  interesting  geological 
features.  The  prevailing  rocks  in  the  county  are  the  Franciscan 
(Jurassic)  serpentines  and  slates  and  Tertiary  volcanics.  There  is  a 
small  area  of  Pliocene,  and  an  area  of  Quaternary  near  Clear  Lake, 
besides  some  undifferentiated  Tertiary  formations  at  the  southern 
extremity  of  Clear  Lake.^ 

^Mineral  ]n-oduction  in  the  i)ast  has  beeji  comjiai'atively  small,  and  has 
been  largely  confined  to  quicksilver  and  mineral  water.  Some  of  the 
leading  minerals  found  in  this  section,  in  part  as  yet  undevelo])ed,  are 
borax,  clay,  copper,  gems,  gold,  gypsum,  mineral  water,  quicksilver, 
silver,  and  sulphur. 

The  entire  county  is  but  sparsely  settled,  and  is  without  rail  connec- 
tions. Besides  the  production  of  minerals,  the  population  is  engaged 
in  farming,  stock  raising,  and  the  operation  of  summer  resorts  at  the 
numerous  mineral  springs  in  tlie  county,  and  on  the  shores  of  Clear 
Lake. 

Clay    Resources. 

The  county  was  visited  by  the  author  in  September,  1925,  and 
attempts  were  made  to  examine  clay  occurrences  that  had  been  repoi'ted 
previously  by  the  Bureau,-  in  which  had  been  mentioned  a  line  of 
kaolin  deposits  near  the  Mount  Sam  Quicksilver  Mine,  and  undeveloped 
deposits  at  Glenbrook,  Kelseyville,  Soda  Bay,  and  Sul])hur  Bank. 
Tmpiiry  was  made  among  local  inhabitants,  and  a  number  of  localities 
were  visited,  but  no  evidence  of  tiicsc  dei)osits  could  be  discovered.     As 

1  Smith.  .T.  P..  The  geologic  formation.s  of  California:  Gal.  State  Min.  Bur.  Bull. 
72.  and  geologic  map. 

=  Bull.  38,  IX  361.     Rept.  IX,  p.  303  ;  XIV,  204.     Prel.  Kept.  7,  p.  49. 


92 


DIVISION   OP   MINES  AND   MINING 


time  was  not  available  for  prospecting,  the  search  was  abandoned.  It 
is  obvious  that  only  a  deposit  of  exceptionally  high-yrade  clay  would 
have  commercial  value  in  this  region,  on  account  of  the  cost  of  trans- 
portation to  market,  and  while  the  possibility  that  such  a  deposit  may 
be  found  can  not  be  entirely  eliminated,  it  is  unlikely. 

Common  brick  clay  is  not  abundant  in  this  region,  but  there  is  little 
likelihood  that  a  brick  yard  will  ever  be  established  on  account  of  lack 
of  market.  A  few  samples  of  common  clays  were  taken  from  deposits 
near  Kelseyville,  but  only  one  of  these,  No.  188,  was  tested.  This  is 
a  clay  shale  from  an  undeveloped  exposure  1.4  miles  southeast  of 
Kelseyville  on  the  Lower  Lake  road.    The  test  results  are  on  page  336. 


General    Features. 


LASSEN    COUNTY. 


Lassen  County  is  in  the  northeast  portion  of  the  state,  south  of 
Modoc,  which  is  the  northeasternmost  county.  Its  area  is  4531  square 
miles,  and  the  po])ulation  is  8507  (1920  census).  It  is  a  succession  of 
mountain  ranges  and  high-altitude  plateaus,  and  is  only  partly  devel- 
oped. Almost  the  entire  area  of  the  county  is  covered  with  Tertiary 
and  Quaternary  lavas.  In  the  vallej's  and  around  the  shores  of  lakes 
are  Quaternary  sediments.  Occurrences  of  cop])er,  gems,  gypsum, 
gold,  silver,  and  sulphur  are  known.  There  is  a  small  annual  produc- 
tion of  gold,  silver  and  miscellaneous  stone. 

Clay    Resources. 

The  county  was  not  visited  in  the  course  of  the  ])resent  investigation. 
It  is  obvious  that  only  clays  having  exceptional  unit  value  could  be 
commercially  produced  in  the  region.  A  deposit  of  clay  is  reported  on 
the  Anderson  Kanch,  at  Hayden  Hill,  owned  by  H.  P.  Anderson,  but 
details  are  lacking.  Hayden  Hill  is  a  gold  mining  district.  It  is  pos- 
sible that  kaolinization  of  some  of  the  rhyolite  tuffs,  especially  those 
high  in  alumina,  that  are  known  to  occur  in  this  district,  may  have 
resulted  in  the  development  of  high-grade  clays. 

In  Preliminary  Report  7,  ]).  49  (1920),  the  following  notes  are  given: 

"J.  E.  Pardee,  Susanville.  Common  brick  clay.  No  recent  pro- 
duction. 

"A.  E.  P>uchler,  Susanville.  Formerly  operated  a  clay  deposit,  but 
no  recent  production." 

No  recent  data  are  available. 


LOS  ANGELES  COUNTY.' 
General    Features. 

Los  Angeles  County  is  bounded  on  the  north  by  Kern  County,  on 
the  east  by  San  Bernardino  County,  on  the  south  by  Orange  County, 
and  on  the  west  by  Ventura  County  and  the  Pacific  Ocean. 

The  ocean  shore  line  extends  for  about  ninety  miles.  The  county 
comprises  4067  square  miles,  a  large  part  of  which  is  mountainous. 
The  population,  according  to  the  1920  census,  is  936,438. 

The  chief  topographic  features  of  the  county  are  the  mountain 
ranges,  the  valle\s,  and  the  great  Los  Angeles  Plain   which  stretches 


1  Tiu-ker.  W.  B..  I^os  Aiife'elt-s  County.  Slati-  Mineralngi.'^f.s  Report  XXIII.  p.  287. 
et  sen.  No  data  on  the  ceramic  industry  are  given  in  thi.s  reference,  but  Mr.  Tucker's 
general  description  of  the  county  was  freely  drawn  upon. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  93 

Iroiii  the  footliills  t<i  llic  sen.  The  liiLiiicst  jx'iiks  of  the  nioiiiiljiins  are 
ill  the  San  (Jahriel  i\aii<ic,  in  the  iidit  lieastern  part  ol'  llie  c-ounty,  and 
arc  over  10, ()()()  I'eet  liijili.  Other  iaiiji:es  in  the  eounly  ai"e  the  Santa 
Susana  and  Santa  Monu-a.  The  San  (lahiiel  ilan.ue  is  ehielly  formed 
of  crystalline  roeks,  with  its  central  axis  eonsistinji:  of  granite,  with 
gneisses  and  schists  on  its  flanks.  The  Santa  Susana  and  Santa  Monica 
i-anges  are  chiefly  formed  of  Tertiary  setlimentary  rocks. 

There  is  oidy  a  small  i)r()diiction  of  metals  in  Los  Angeles  County, 
its  principal  iiiiiicial  wealth  being  in  struct  ural  and  industrial  materials, 
petroleum,  and  natural  gas.  Since  1923,  Ijos  Angeles  County  has  led 
all  other  counties  of  the  state  in  the  value  of  its  mineral  j)r()duction, 
largely  due  to  its  i)etroleum  jjroduetion. 

Among  its  mineral  resources  may  be  noted  asi)halt,  barytes,  borax, 
brick,  clay,  eoi)i)cr,  diatonnte,  fuller's  earth,  gems,  gold,  gypsum,  lead, 
limestone,  marble,  mineral  j)aint,  mineral  water,  natural  gas,  petroleum, 
glass  sand,  sandstone,  serpentine,  silver,  soapstone,  miscellaneous  stone, 
and  zinc. 

Clay   Resources. 

Los  Angeles  county  is  especially  fortunate  in  that  there  is  an  ample 
supi)ly  of  common  clay  and  sliale  for  the  manufacture  of  heavy 
structural  ware,  such  as  common  brick,  hollow  tile,  roofing  tile,  sewer 
pipe,  etc.  Close  to  the  metropolitan  area  of  the  city  of  Los  Angeles 
are  numerous  deposits  of  shale  and  loam  that  have  been  in  use  for 
many  years  for  the  manufacture  of  these  products.  Property  values 
have  increased  to  such  an  extent  in  recent  years  that  many  of  these 
deposits  have  been  sold  for  business  or  industrial  purposes,  but  there 
are  still  a  number  of  plants  in  operation  within  a  radius  of  one  mile 
from  the  business  center  of  the  city.  In  the  outskirts  of  the  city,  on 
almost  every  side,  Avithin  a  radius  of  20  miles  from  the  downtown  sec- 
tion, are  numerous  clay  and  shale  deposits  that  are  being  utilized  by 
the  ceramic  iiidustry.  Perhaps  the  most  important  of  these  deposits 
is  in  Santa  Monica,  where  a  number  of  brick  yards  have  been  estab- 
lished, and  from  which  clay  is  mined  for  use  in  other  plants  of  the 
county.  The  Santa  ^Monica  clay  is  not  only  suitable  for  the  manufac- 
ture of  common  brick,  but  is  extensively  used  in  hollow  tile,  roofing 
tile,  scwei-  pipe,  electric  conduit,  face  brick,  and  other  structural  ware 
bodies. 

No  high-grade  clays  are  produced  in  the  county.  It  is  claimed  that 
high-grade  clays  occur  on  the  Malibu  Ranch,  north  of  Santa  Monica 
(see  under  ]\Ialibu  Pottery),  but  these  have  not  been  extensively  ])ros- 
pected,  and  at  this  writing  little  information  was  available  as  to  the 
extent  and  character  of  these  clays. 

On  account  of  extremely  favorable  industrial  conditions  in  the  Los 
Angeles  district,  with  a  combination  of  cheap  power,  fuel  and  labor, 
adequate  spur  track  facilities,  equable  climate,  and  an  extensive  market 
arising  from  the  rapid  growth  of  the  region,  there  are  a  large  number 
of  ceramic  plants  in  the  county,  and  practically  every  commercial  type 
of  ceramic  ware  is  being  manufactured  in  one  or  more  plants.  The 
high-grade  clays  needed  by  the  industry  are  largely  obtained  from  the 
Alberhill-Corona  deposits  in  Riverside  County  and  from  deposits  in 
Orange  and  San  Diego  counties.  The  freight  rate  on  clays  from  the 
Alberhill  district  is  about  $0.90  per  ton,  in  carload  lots,  and  the  costs 


94  DIVISION   OF    MIXES   AND   MINING 

of  miniiiy  are  relatively  low,  so  that  most  grades  of  clay  from  Alberhill 
can  be  delivered  in  Los  Angeles  at  a  cost  of  $2  to  .^6  per  ton.  Some 
Lincoln  and  lone  clays,  from  Placei-  hiuI  Aniadoi-  counties,  respectively, 
are  shipped  into  Los  Angeles  for  use  in  the  manufacture  of  terra  cotta. 
floor  tile,  stoneware,  and  ])()ttery.  English  china  and  ball  clay,  and 
clays  from  Florida  and  Kentucky  are  also  imported  for  the  manufac- 
ture of  whiteware  and  tile,  at  a  cost  of  $14  to  $25  per  ton,  delivered. 
Southern  California  abounds  in  deposits  of  feldspar  and  silica, 
especially  in  San  Diego  and  Riverside  counties,  so  that  these  materials 
may  be  secured  by  the  local  industry  at  comparatively  moderate  cost. 

Descriptions  of  individual  clay  deposits  and  ceramic  plants  follow. 
The  field  work' was  done  during  the  summers  of  1925  and  1926,  and 
the  industry  has  been  growing  and  changing  rapidly,  so  that  it  is 
obviously  impossible  to  present  the  latest  information  on  all  plants. 
Attempts  were  made  by  correspondence  to  bring  all  material  up  to  date 
as  of  November,  1927,  but  in  many  cases  no  replies  had  been  received 
at  this  writing.  Mr.  Tucker,  of  the  ^Mining  Division,  rendered  valuable 
service  in  obtaining  data  on  a  number  of  plants  in  November  and 
December,  1927. 

Acme  Brick  Compayixj}  Thos.  Kelley,  president ;  R.  L.  Worthington, 
secretary.  Office  and  plant  in  Santa  Monica.  The  company  owns  20 
acres  of  land  and  manufactures  common  brick  only.  The  dei)osit  con- 
sists of  20  to  30  feet  of  red  and  yellow  clay,  overlain  by  two  feet  of  soil. 
The  clay  is  mined  in  an  open  pit  by  a  gasoline  shovel,  which  loads  into 
3-ton  side  dump  cars.  The  cars  are  hoisted  up  an  incline  to  a  hopper 
at  the  plant. 

The  soft-mud  process  is  used.  The  clay  is  ground  in  a  dry  pan, 
elevated  by  a  bucket  elevator  to  a  ^-inch  impact  screen,  ])ugged  in  two 
pug-mills  in  series,  and  finally  i)asses  to  the  brick  ])ress.  which  has  a 
capacity  of  60,000  brick  i)er  day.  The  oversize  from  the  .screen  is 
returned  to  the  dry  pan  for  regrinding. 

Conveyors  are  used  to  transport  the  brick  to  and  from  the  drier, 
which  is  heated  by  steam  from  two  150-h.]).  oil-fired  boilers.  Drying  is 
completed  in  from  24  to  36  hours. 

Six  oil-fired  field  kilns  are  in  use,  having  a  capacity  of  600,000  brick 
each. 

The  plant  operates  thronghout  the  year.  Forty  men  are  employed, 
and  135  h.p.  of  electric  power  are  installed. 

AJhamhra  Kilns,  Inc.  E.  H.  Ockerman.  Alhambra.  The  company 
now  operates  two  plants,  one  at  Alhambra  and  the  other  at  Santa 
Monica.  The  site  of  the  Alhambra  plant  was  visited  by  the  author 
shortly  after  construction  was  .started,  in  September,  1926.  A  request 
for  recent  information  was  addressed  to  the  company  on  November  11, 
1927,  but  no  reply  had  been  received  at  this  writing.  It  is  known  that 
hand-made  roofing  tile  and  patio  floor  tile  are  being  made. 

American  China  Company.  W.  N.  Reeves,  oAvner,  2304  East  Fifty- 
second  Street,  Los  Angeles.  This  company  specializes  in  single-burn, 
glazed  tile,  ready-set  for  soda  fountains,  fire  places,  etc.  A  portion  of 
the  tile  used  is*  made  at  the  plant  from  Alberhill  clays,  principally 
E-101  and  SH-4  (samples  No.  11,  p.  257.  and  273,  p.  273),  and  also 

•  Data  supplied  by  W.  B.  Tucker,  district  mining  engineer,  December,   1927. 


CLAY  RESOTMtCES  AXD  rERA:\ri('  TXHUSTRY  95 

some  clay  from  the  Emsco  i)it  near  Corona.     The  balance  of  the  tile  is 
])ureliase(l  from  tlie  (Vilifornia  Clay  Products  ('oiui)any. 

The  wai-c  is  huriicd  for  2f  lionrs  in  a  jias-fii'ed  Uilii  liaviii<i'  a  ca])acity 
(tf  400  s(|iiare  feet  oi'  tile.  The  output  of  tlie  plant  varies  Avitli  the 
demand  up  to  70,000  s(|.  ft.  per  year. 

American  Encmistic  Tiling  T'o.,  Ltd.  Fraidv  A.  Philo,  general  man- 
ager, Crawford  Massey  and  ]Mr.  Schreiber,  ceramists.  Los  Angeles 
idant  at  2080  East  Fifty-second  Street ;  Hermosa  F.each  ]dant  at  700 
Fifteenth  Street.  Tlu^  Ijos  Angeles  i)lant  -was  built  by  the  West  Coast 
Tile  Company  and  ]iurcliased  in  1919  by  the  American  Encaustic  Tiling 
Co.,  Ltd.,  a  nationally  luiown  manufacturer  of  ceramic  floor,  wall,  and 
decorative  faience  tih\  witli  jdauts  at  Zanesville,  Ohio,  and  JNIaurer, 
X.  J.,  and  witli  head  ot^ces  at  16  East  Foi'ty-first  Street,  New  York 
City.  The  Ilermosa  Beach  plant  was  purchased  by  the  company  from 
the  Prouty-line  Products  Company  in  1925. 

The  company  marl^ets  a  com])lete  line  of  vitrified  and  semi-vitrified 
glazed  and  unglazed  floor,  wall,  and  decorative  faience  tile.  Both  the 
Los  Angeles  and  Ilermosa  Beach  plants  manufacture  a  large  variety 
of  colors  in  glazed,  unglazed,  and  decorative  tiles. 

With  such  a  diversity  of  products,  it  is  natural  that  the  raw  mate- 
rials in  use  at  the  plant  cover  a  wide  range.  It  has  been  found  that  in 
order  to  minimize  plant  difficulties,  and  to  secure  a  uniformly  high- 
grade  product,  it  is  necessary  to  use  a  good  quality  of  English  china 
clay,  Florida  kaolin,  English  and  Kentucky  ball  clays,  in  practically 
all  of  the  white  or  nearly-white  burning  mixtures,  rather  than  to 
attempt  to  rely  upon  California  materials.  However,  some  of  the  clays 
used  at  the  Los  Angeles  plant,  and  all  of  the  clays  used  at  the  Ilermosa 
Beach  plaiit,  are  obtained  in  the  State  of  California.  Quartz  and 
feldspar  are  obtained  maiidy  from  tlie  large  deposits  owned  by  the 
company  in  Riverside  County.  The  company  also  owns  a  deposit  of 
'Cornish  Stone'  (Sample  No.  58),  at  Dehesa,  San  Diego  County,  which 
is  used  as  an  ingredient  of  a  hard,  white,  vitrified  tile,  known  under 
tlie  trade  name  of  "Kaospar. " 

The  Los  Angeles  i)lant  covers  about  3^  acres  and  the  Hermosa  Beach 
plant  about  2|  acres.  Both  ])lants  are  completely  equipped,  well 
arranged,  and  efficiently  operated.  At  the  Los  Angeles  plant  all  of 
the  materials  entering  tlie  ])lant  are  ground  in  mills  suited  to  each 
material,  and  imrticular  care  is  exercised  to  avoid  contamination  with 
iron.  This  necessitates  the  use  of  wood  or  porcelain  liners  in  the 
pebble  mills  for  grinding  to  ])ass  140-mesh  screen.  Imported  Danish 
flint  pebbles  are  used  as  local  pebbles  have  proved  to  be  lacking  in 
hardness.  After  grinding,  the  mixtures  are  prepared  by  adding  the 
])roper  amount  of  each  material  to  double  blungers.  The  'pulp'  is 
then  treated  in  filter  presses,  dried  in  gas-heated  dryers  to  about  10% 
moisture,  broken  through  20-mesli  screen,  tempered  with  sufficient 
moisture  to  insure  the  proper  consistency  for  dry  pressing,  and  stored 
in  bins  until  ready  for  use. 

Most  of  the  tiles  are  formed  by  dry  pressing,  using  either  power- 
driven  or  hand-operated  presses,  depending  upon  the  quantity  of  each 
size  and  color  required  as  well  as  the  shape  of  the  tile. 

At  the  Los  Angeles  plant  the  bodies  are  fiired  in  12  gas-heated  bee- 
hive kilns,  approximately  20  feet  in  diameter  by  12  feet  high.     The 


96  DIVISION   OF    MINES  AND  MINING 

firing  sclitHlule  requires  foiu-  to  five  dnys  lieatiiij;',  and  tliree  to  four 
daj's  cooling,  the  maximum  tem])eratnre  corresponding  to  cone  11 
(1285°  C).  Ui)on  the  completion  of  this  firing,  the  tiles  that  are  to  be 
glazed  are  transferred  by  truck  to  the  glazing  room  -which  is  in  a  sepa- 
rate building  a  short  distance  from  the  biscuit  kilns.  After  ap])h4ng 
the  glaze  mixture,  the  tiles  are  re-fired  in  a  Harrop  tunnel  kiln  which 
is  approximately  250  feet  long,  8  feet  wide,  and  8  feet  high.  The  glost 
cycle  occupies  about  54  hours,  reaching  a  maximum  temperature  corre- 
sponding to  cone  01  (1110°  (J.).  At  the  Ilerniosa  Beach  plant  both  the 
biscuit  ware  and  the  glazed  ware  are  fired  in  five  specially-designed 
tunnel  kilns,  the  firing  temperature  being  about  the  same  as  that  used 
at  the  Los  Angeles  plant. 

All  temperatures  are  controlled  by  the  use  of  a  pyrometer,  either  of 
the  intermittent  or  continuous  recording  type. 

Each  plant  is  equipped  with  a  machine  shop  for  making  all  ordinary 
repairs,  and  for  making  the  dies  used  in  the  presses.  A  complete 
experimental  laboratory,  equipped  with  ball  mill,  mixing  pans,  blunger, 
filter  press,  etc.,  in  charge  of  an  experienced  ceramic  engineer,  is  main- 
tained at  each  plant  for  the  purpose  of  studying  bodies  and  glazes, 
and  to  aid  in  the  solution  of  operating  difficulties. 

Both  plants  together  employ  ap])roximately  600  persons. 

All  tiles  sold  by  the  American  Encaustic  Tiling  Co.,  Ltd.,  are  made 
by  them  in  their  own  plants  in  the  L^nited  States  of  America. 

Bibl:  State   Min.   Bur.    Prel.    Kept.   No.   7,   p.    62    (West    Coast 
Tile  Co.). 

American  Refractories  Company.  F.  E.  Keeler,  president;  Earl 
McClintock,  vice  president ;  G.  Raj'  Boggs,  general  manager  and  secre- 
tary-treasurer.    OfBce  and  plant  at  3232  Alosta  Street,  Los  Angeles. 

This  compam^  is  engaged  in  the  manufacture  of  fii'e  brick  for  flue 
linings,  kilns  and  boiler  settings,  and  silica  glass-tank  blocks.  One  of 
the  si)ecialties  is  the  manufacture  of  radiant  stove  backs. 

The  company  controls  the  Hunter  Ranch  clay  deposit  in  Orange 
County  (samples  63  and  64),  and  purchases  other  clays  from  the  Alber- 
hill  district. 

The  clays  as  received  at  the  plant  are  stock  piled,  from  which  they 
are  fed  hy  wheelbarrows  in  the  proportions  desired  for  the  various 
mixes  to  an  8-ft.  dry  pan.  The  dry  pan  ])roduct  is  elevated  to  a 
screen,  which  delivers  oversize  to  the  dry  pan  for  regrinding,  and 
undersize  to  a  double-shaft  and  a  single-shaft  pug-mill  in  series.  From 
the  pug-mills,  the  plastic  mix  is  fed  to  an  American  auger  machine. 
All  machine-made  brick  are  repressed  in  a  Raymond  press.  Some 
grades  of  brick,  particularly  the  'Arc'  brand,  are  made  by  hand 
molding,  and  all  special  shapes  and  glass-tank  blocks  are  hand  molded. 

After  shaping,  the  ware  is  transferred  on  hand  trucks  to  a  waste- 
heat  drying  floor.     Drying  usually  requires  about  three  days. 

The  radiant  stove  backs  are  made  by  dry  pressing,  and  are  fired  in 
two  down-draft  rectangidar  kilns,  7-f't.  by  9-ft.  and  6-ft.  by  8-ft.  in 
size.  Brick  and  other  shapes  are  fired  in  four  28-ft.  round  down-draft 
kilns.  Natural  gas  is  used  for  all  firing.  The  round  kilns  are  fired 
to  cone  13  (1350°  C.)  in  ten  days  and  are  cooled  by  the  aid  of  exhaust 
fans  in  six  days.  Allowing  five  days  for  drawing  and  setting,  the 
complete  cycle  requires  21  days. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  f)7 

The  capacity-  of  llir  plant  is  ir),()()()  sfaiulard  !)-in.  brick  a  da.w  or  its 
i'(piival('ii1  ill  (ttlicr  \\;ii('.     Twonty-five  iiicii  ai'(>  employed. 

Angulo  Tile  Cotnpanif.  riant  No.  2;  R.  F.  Anfrulo  and  Sons,  owners. 
Tliis  company  lias  two  plants  en^a^cd  in  the  mannfactui-e  of  hand-made 
Mission  roof  and  terrace  tile.  Plant  No.  2  is  at  Reseda,  Los  Anyeles 
County,  and  Plant  Xo.  1  is  in  Santa  Barbara  (see  nnder  Santa  I^>arbara 
County).  The  Reseda  i^lant  is  llie  larm'r  operation.  Clay  is  obtained 
from  a  surface  de])osit  adjoininji'  the  plant.  A  tile  maeliine  ha.s  recently 
(November,  1927)  been  added  to  the  ecpiipment.  The  company  has  a 
V.  S.  i)atent  on  a  s])ecial  method  of  making-  hand-made  rooting  tile. 
The  ])lant  is  eqnii)ped  willi  three  kilns,  fired  with  gas  and  oil. 

Atlas  Fire  Brick  Comimmi.  M.  I.  Power,  president;  C.  J.  Walters, 
vice  i)resident ;  Stuart  Findley,  secretary;  Clifford  Tillotson,  manager. 
Office  and  plant  at  P>oyle  and  Slauson  avenues,  Los  Angeles. 

This  comi)any  specializes  in  the  manufacture  of  silica  brick  and  high- 
grade  fireclay  brick.  In  addition  to  standard  straight  fire  brick  and 
silica-brick  shapes,  the  company  is  prepared  to  make  all  key  and  arch 
shapes,  glass-tank  l)locks,  and  special  shapes. 

The  raw  materials  in  use  include  the  Emsco  white  pla.stic  fireclay 
(sample  No.  70,  p.  272)  from  Riverside  County,  German  fireclay  (sam- 
ple No.  56,  p.  297)  and  ganister  from  the  coiii])any's  deposit  near  Hicks, 
San  Bernardino  County.  From  6000  to  12,000 'tons  of  clay  and  :5000 
to  -lOOO  tons  of  ganister  are  used  each  year. 

The  mixtures  are  prepared  by  dry-pan  grinding,  followed  by  pugging. 
All  ela,y  brick  mixtures  are  repugged,  and  then  aged  in  a  moist  room  for 
a  period  ai)i)roximating  two  weeks.  The  silica  brick  are  all  hand  molded. 
Special  care  must  be  taken  with  the  large  glass-tank  blocks,  to  ensure 
thorough  tamping  during  molding.  Fire  brick  are  made  by  either  the 
dry  i)i-ess  or  wet  process,  the  latter  being  by  hand  molding,  followed  by 
repressing. 

All  shapes  are  air  dried,  then  fired  in  gas-fired  round  down-draft 
kilns.  Fire  brick  are  fired  to  cone  12  (1310°  C.)  and  to  cone  14 
(1390°  C.)  ;  glass-tank  refractories  to  cone  12;  and  silica  brick  up  to 
cone  18  (148o°  C).  Seven  kilns  are  in  operation,  and  40  men  are 
employed. 

Batchelder-Wilson  Co.  E.  A.  Batchelder  and  L.  H.  Wilson,  owners. 
Office  and  plant  at  2633  Artesian  Street,  Los  Angeles.  This  company, 
formerly  known  as  the  Batchelder  Tile  Comjiany,  specializes  in  decor- 
ative tile  for  homes,  and  their  arti.stic  products  have  become  well-known 
throughout  the  region  west  of  the  Rocky  JMountains.  The  ])rincipal 
products  are  facing  and  paving  tile  for  interior  decorating.  Some 
architectural  terra  cotta  is  i)roduced  for  entrance  ways  and  interiors. 
The  clays  used  are  Hill  blue  (samjjle  No.  9,  p.  287),  extra  select 
main  tunnel  (sample  No.  18,  p.  321)  and  some  pink  mottled  (sample  No. 
7,  p.  328),  supplied  by  the  Alberhill  Coal  and  Clay  Company  in  River- 
side County  ;  Lincoln  No.  1-6  (sample  No.  146,  p.  303),  from  the  Lincoln 
Clay  Products  Company  in  Placer  County;  Bacon  red  (sample  No. 
127,  p.  335),  and  Harvey  (sami)le  No.  133,  p.  298),  from  lone,  Amador 
County,  and  a  small  quantity  of  Santa  IMonica  clay  (represented  by 
sample  No.  61,  p.  341).  Some  bentonite  from  a  deposit  near  Araboy,  San 
Bernardino  County,  is  used  in  the  nnderglazing  slip. 

7—54979 


98  DIVISION   OF    MINES   AND   MINING 

Six  standard  mixtures  are  used,  jTrading  in  fired-body  color  from  red 
to  cream.  The  mixtures  are  i)rei>ared  by  jaw  erushiiiK,  roller-mill  .grind- 
ing, and  final  png-mill  mixinf;  and  tempering.  The  batches  are  seasoned 
in  moist  rooms  before  pressing,  a  i)eriod  of  at  least  two  weeks  being 
preferred. 

All  of  the  jn-oducts  are  hand  moulded  in  plaster  molds,  which  are 
made  in  the  plant.  The  drying  is  in  air,  followed  by  automatic  drying 
ovens.  The  total  drying  time  is  about  48  hours.  After  drying,  an 
underglaze  slip  is  sprayed  on,  followed  by  the  color  decorations,  Avhich 
are  ])ainted  by  hand. 

The  kiln  equipment  includes  two  7  x  12  foot  rectangular  kilns, 
two  20-foot  round  down-draft  kilns,  and  one  200-foot  tunnel  kiln,  all 
gas  fired.  A  great  variety  of  colors  from  the  same  body  and  glaze  is 
produced  by  varying  the  temperature  and  atmospheric  conditions  dur- 
ing firing.  Pyrometers  and  cones  are  used  on  all  kilns  for  controlling 
temperatures. 

After  firing,  some  of  the  tile  are  buffed  on  emery  wheels  to  remove 
a  part  of  the  glaze.  This  is  followed  by  several  sprays  of  raw  lin.seed 
oil,  thus  producing  a  pleasing  mottled  effect. 

Monorail  transportation  is  used  throughout  the  plant. 

A  small  testing  laboratory,  in  charge  of  a  ceramic  graduate,  is 
maintained. 

J.  A.  Bauer  Pottery  Co.  W.  E.  Bachman,  president,  415  West 
Avenue  Thirty-three,  Los  Angeles.  This  is  a  four-kiln  pottery  making 
a  complete  line  of  red  flower  pots,  white  stoneware,  yellow  bowls, 
crocks,  vases,  and  olla.s.  Santa  ]\Ionica  clay  (sam])le  Xo.  61,  p.  341)  is 
used  for  flower  pots  and  ollas,  while  Alberhill  and  Lincoln  clays  are 
used  for  the  light-colored,  vitrified  stoneware  bodies.  Approximately 
4000  tons  of  clay  are  consumed  per  year. 

The  clays  are  spray-washed  to  remove  surface  contamination,  then 
pugged.  Flower  pots  and  some  of  the  other  ware  are  machine  molded. 
For  other  products  turning  (' jiggering')  or  hand  moulding  are  used. 
All  of  the  smaller  ware  is  dried  in  24  hours,  natural  gas  auxiliary 
heating  being  used  in  the  drying  room.  White,  yellow  or  cream  glazes, 
where  used,  are  applied  by  dipping  before  firing.  A  single  firing 
matures  both  the  body  and  the  glaze. 

The  four  kilns  are  of  the  round  down-draft  type,  fired  with  gas,  but 
equipped  to  burn  oil  if  necessary  or  desirable.  The  red  ware  is  burned 
to  a  temperature  of  1850°  F.  in  three  to  four  days,  and  the  cream  body 
ware  is  fired  to  2250°  F.  in  about  the  same  time.  One  of  the  kilns  is 
ordinarily  operating  on  the  light  colored  body,  and  is  equipped  witli 
pyrometric  control. 

At  present  this  is  the  only  plant  in  Los  Angeles  manufacturing  floAver 
pots.  Not  over  half  of  the  company's  business  is  in  flower  pots,  but 
this  constitutes  the  largest  single  item.  In  order  to  permit  the  full 
time  operation  of  the  plant  on  a  systematized  plan,  a  stock  of  ware 
aggregating  over  $100,000  in  value  is  constantly  kept  on  hand. 

Fifty  men  are  employed. 

Bibl :  Cal.  State  Min.  Bur.  Prel.  Kept.  Xo.  7,  p.  50. 
California  Brick  and  Tile  Company.^      (Formerly  the  Owens  Brick 


Data  supplied  by  W.   B.  Tucker,  district  mining  engineer,   December,   1927. 


CLAY  RESOURCES  AND  CERAMIC  TKDTTSTRY  99 

Company.)  K.  A.  Miller.  ])resi(l(iit  ;  11.  W.  Urou^hton,  secretary. 
Office  and  i)iant  at  (}1.')9  Kcstcr  Street,  Van  Nuys.  The  company  owns 
*J(t  aeres  of  land,  and  mannl'actni'es  cojnnion  bi-ick  only. 

TIk'  de[)osit  consists  of  red  and  yellow  clay,  20  to  .']()  feet  tliick, 
nnderlyinji:  an  overhnrden  of  soil  Jroni  one  to  two  I'eet  tliick.  The 
clay  is  excavated  from  an  open  pit  by  a  <iasoline  shovel,  which  loads 
into  .S-ton  cars.  A  ji'asoline  motor  lianls  the  cai-s  from  tlie  ])it  and 
delivers  the  clay  to  two  hoppers  at  the  ])Iant. 

From  the  hojjpers  the  clay  is  delivered  l»y  two  ])ai'allel  belt  con- 
veyors to  two  dry  i)ans.  The  ])roduct  from  the  i)ans  is  elevated  by  two 
bucket  elevatoi's  to  two  wire  screens,  which  deliver  the  nndersi/e  to  a 
centi'al  hopper,  and  return  the  oversize  to  the  dry  pans.  From  the 
hoppers,  the  clay  is  fed  to  a  ])ng-mill,  then  to  an  au<i('r  machine, 
eqni])i)ed  with  a  wire  cutter. 

From  the  take-off  belt  followinii-  the  wire  cutter,  the  brick  are  loaded 
on  drier  cars.  A  16-track  tunnel  di'ier  is  used,  which  is  120  feet  lonii, 
60  feet  wide,  and  6  feet  high,  and  has  a  capacity  of  7o,()()()  brick  \)ov 
60  hours.  Two  Iladfield-Penfield  blowers,  driven  by  a  .")(l-li.p.  motor, 
circulate  heated  air  from  an  oil-fired  furnace  to  the  drier. 

Six  natural-gas-fired  held  kilns  are  in  use,  having  a  capacity  of  ToO,- 
000  to  1,000,000  brick  each. 

.Machinery  in  the  plant  is  driven  by  a  IfiO-h.p.  Western  gas  engine. 
Tlie  plant  operates  tlironghout  the  year,  and  40  men  are  employed. 

Ciilifoniia  Clan  Piuducfs  Co.  Victor  Kremer,  president.  "Victor 
Kremer  Enteri)rises,  Inc.,"  315  West  Mutual  Life  ]>uilding,  321 
West  Third  Street,  Los  Angeles.  The  plant  is  in  South  Gate.  This 
factory  manufactures  an  extensive  line  of  glazed  wall  tile  and  ceramic 
floor  tile.  English  china  and  ball  clays  are  used  in  the  white-burning 
bodies,  but  Lincoln  clay  (sample  Xo.  146,  p.  303)  from  Placer  County 
and  Cardiff  fire  clay  (sample  No.  36,  p.  311)  from  the  company's 
property  in  San  Diego  county  are  used  in  the  cream,  buff  and  darker- 
colored  bodies. 

The  finer  cla\s  to  be  used  in  the  manufacture  of  white  bodies  and 
other  high  grade  ware,  are  ])repared  by  blunging  and  filter  pressing 
the  ground  material.  Plastic  clay  mixtures  are  prepared  in  ])ug  mills, 
and  ai'e  well  seasoned  before  use. 

Dry-pressed  floor  and  wall  tile  are  made  in  hand-operated  ])resses. 
PMoor  and  wall  tile  with  an  undulating  surface  are  produced  by  hand 
l)ressing  of  pugged  clay  in  ])laster  molds.  The  latter  are  highly  prized 
by  architects  to  secure  certain  artistic  effects,  as  the  undulating  sur- 
face gives  the  impression  of  wear  resulting  from  long  use. 

Drying  is  done  Avith  hot  air,  in-oduced  by  waste  heat.  The  drying 
time  varies  from  24  to  36  hours  depending  upon  the  size  of  tile. 

^lonochrome  glazes  are  api)lied  by  hand  dipping  in  the  glaze  slip. 
Polychrome  work  is  done  with  a  glaze  bulb.  Some  brush  work  is 
done  in  special  cases. 

All  of  the  glazed  tile  are  given  a  double  firing.  There  are  three 
biscuit  kilns  with  a  firing  cycle  of  72  to  90  hours  to  attain  a  maximum 
temperature  of  2400"  F.  Three  glost  kilns  are  in  use,  with  a  firing  cycle 
of  36  hours  to  1800"  F.  The  apparent  discrepancy  in  the  capacities 
of  the  biscuit  and  glost  kilns  is  explained  by  noting  that  the  tile  are 
packed  in  sand  in  the  biscuit  kiln  saggers,  but  must  be  supported  on 


100  DIVISION  OF  MINES  AND  MiNI^fG 

pins  in  the  glost  sagjj:ers,  hence  requiring-  more  space  per  nnit  of  tile 
area  in  the  latter  case. 

]\Inch  of  the  work  in  the  factory,  sucli  as  api)lyin«?  glazes,  removing 
loose  dust  from  tile  after  dry  pressing,  packing  and  unpacking  of 
saggers,  etc.,  is  of  such  a  nature  that  Avomen  employees  are  used,  men 
being  employed  only  for  the  heavier  duties,  such  as  operating  the 
presses,  trucking,  kiln  setting  or  drawing,  and  firing. 

City  B)'ick  Co.  The  plant  is  at  1900  West  Manchester  Avenue, 
(Eighty-sixth  Street)  and  Western  Street.  This  company  makes 
common  red  brick  only.  The  clay  in  use  is  a  surface  deposit  of  loose 
sandy  loam,  with  just  sufficient  bonding  ])ower  to  ^lermit  the  manu- 
facture of  a  satisfactory  building  brick  by  the  soft-mud  process.  The 
clay  is  mined  in  a  shallow  pit  by  horse  scrapers,  wliich  deliver  the 
material  to  an  incline  tram  whicli  dumps  into  a  hopper  feeding  a 
disintegrator  and  pug  mill,  followed  by  a  6-brick  press.  The  brick 
are  carried  to  the  drying  sheds  by  rope  conveyors.  The  dried  brick 
are  fired  in  gas-fired  open  kilns.  Handling  losses  are  apparently 
higher  than  in  most  i^lants,  on  account  of  the  low  strength  of  the  brick 
in  the  plastic  and  dry  state. 

Claycraft  Potteries,  Inc.  Gus  Larsen,  president;  F.  H.  Koberts,  vice 
president;  W.  C.  Reordan,  treasurer;  Henry  Prussiing,  secretary. 
Office  and  plant  at  3101  South  Fernando  Road,  Los  Angeles.  This 
company  manufactures  faience  art  tile,  using  an  Alberhill  clay  body 
that  matures  at  cone  5  (1180°  C.)  and  applving  glazes  that  mature  at 
cone  4  (1050°  C). 

The  plant  is  equipped  with  two  8-ft.  wet  pans,  two  tile  augers,  a 
sagger  press  and  three  tile  presses,  one  of  which  is  power-driven  and 
has  a  capacity  of  900  tile  per  hour.  All  fancy  i)ieces  are  hand-molded 
in  plaster  molds. 

The  ware  is  dried  in  three  6-ft.  by  7-ft.  by  25-ft.  tunnel  driers.  The 
biscuit  firing  is  done  in  three  '220-ft.  round  down-draft  kilns,  gas 
fired.     Three  muffle  kilns  are  used  for  the  giost  firing. 

Twenty-five  men  are  employed. 

H.  F.  Coors  Co.,  Inc.,  H.  F.  Coors,  manager.  P.  0.  Box  517,  Ingle- 
wood.  This  plant  is  at  419  South  Judah  Street,  Inglewood.  It  was 
established  in  December,  1925,  for  the  manufacture  of  porcelain  plumb- 
ing accessories  and  electrical  specialties. 

English  china  clay  and  Coors  ball  clay  (sample  No.  57,  p.  264), 
Campo  or  Kingman  feldspar,  and  various  grades  of  silica  are  used 
in  the  ])()dy  mixture,  which  is  prepared  by  ball-mill  grinding. 

Some  of  the  ware  is  dry -pressed,  and  some  is  cast.  A  hot-air  drier 
is  used.  An  8-foot  gas-fired  round  down-draft  kiln  is  used  for  both 
the  biscuit  and  the  glost  firing.  A  small  muffle  kiln  is  used  for  decorat- 
ing, which  consists  principally  of  labeling  faucet  handles. 

Davidson  Brick  Co.  Nathan  Davidson,  owner,  5301  Chicago  Avenue, 
Los  Angeles.  This  is  a  well-equipped  and  Avell-arranged  plant  for 
manufacturing  (Common  red  brick.  The  clay  varies  from  an  adobe 
to  a  soft  clay  shale.  Mining  operations  have  exposed  a  bank  60  to  70 
feet  high,  and  300  feet  long.  The  pit  extends  into  a  gentlj^-sloping  hill- 
side above  the  plant.  An  electric  shovel  is  used  for  mining  and  loading 
into  dump  cars,  which  are  hauled  to  the  i)lant  by  a  gasoline  locomotive. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  101 

Brick  are  made  by  the  stiff-mud,  side-cut  process.  A  rope  conveyor 
is  used  to  deliver  the  brick  to  the  drying  sheds.  Oil  fired  field  kilns 
are  used. 

A  sam])le  (No.  60)  of  the  more  shaly  variety  of  clay  was  taken  as 
i-epresentative  of  the  class  of  material  to  be  expected  in  this  district. 
The  tests  (p.  o-tO)  indicate  that  the  drying  and  firing  jjroperties  of 
the  clay  are  not  greatly  different  from  those  of  the  Santa  Monica 
clay  (sample  No.  61,  p.  841),  which  is  widely  used  in  Los  Angeles 
County  as  an  ingredient  of  sewer  pipe,  conduit,  flower  pot,  and  olla 
mixtures. 

Empire  China  Compunj).  Office  and  plant  at  Burbank.  ]\Ir.  ]\Ior- 
gan,  superintendent.  This  is  a  well-equipped  plant,  containing  seven 
round  down-draft  kilns  that  operated  for  a  number  of  years  for  the 
manufacture  of  semi-porcelain  hotel  and  dinner  china.  Experiments 
have  been  in  ])rogress  for  a  number  of  monllis  on  tlie  manufacture  of 
vitreous  dinnerware,  and  the  management  expects  to  start  production 
of  this  ware  during  the  si)ring  of  1928,  using  a  California  feldspar  and 
silica,  Nevada  china  clay,  and  a  certain  amount  of  Florida  clay.^ 

I'J)nsro  Rrfractorics  Conipanij.  E.  M.  Smith,  president.  Office  and 
plant  in  Southgate,  at  Manchester  Avenue  and  Atlantic  Boulevard. 
This  company  was  established  in  1927,  and  was  not  visited  by  the 
author,  such  data  as  are  included  here  having  been  supplied  by  the 
com{)any.  The  company  manufactures  fire  brick,  silica  brick  and  glass- 
tank  refractories.  The  clays  are  obtained  from  El  Toro,  Orange 
County.  (Hunter  Ranch  ?,  see  samples  No.  63,  64  and  268,  p.  260), 
and  from  the  Emsco  pit  in  the  Alberhill  district,  Riverside  County. 
Eight  gas-fired  kilns  are  in  use. 

Gladding,  McBean  and  Companij.  Southern  Division.  Atholl 
^McBean,  ])resident;  Fred  B.  Ortman,  vice  president.  Los  Angeles  office 
at  621  South  Hope  Street.  In  1926  this  com])any  merged  with  the 
Los  Angeles  Pressed  Brick  Company.  The  Southern  Division  of  the 
com])any  includes  the  following  ])lants :  the  Alberhill  (see  under  River- 
side County),  Santa  ]\Ionica  and  Los  Angeles  plants,  all  formerly  owned 
by  the  Los  Angeles  Pressed  Brick  Company ;  and  the  Tropico  plant. 
The  company  also  owns  the  Goat  Ranch  clay  deposit  in  Orange  County 
(see  under  Orange  County). 

Los  Angeles  Plant.  952  Date  Street,  Los  Angeles.  This  is  the 
largest  of  the  plants  formerly  owned  by  the  Los  Angeles  Pressed  Brick 
Com])any,  and  has  perhaps  the  greatest  manufacturing  resources  of  the 
southern  California  plants  of  Gladding,  McBean  and  Company.  The 
])roducts  made  at  this  plant  are  terra  cotta,  face  brick,  'quarry'  tile, 
and  roofing  tile.  The  plant  is  in  the  heart  of  the  Los  Angeles  com- 
mercial district  and  all  clay  must  be  shipped  in. 

The  terra  cotta  mixtures  are  the  same  as  tho.se  in  use  at  the  Tropico 
plant,  described  below,  and  are  prepared  in  the  same  manner  by  dry 
pans  and  pug-mills,  followed  by  a  variable  period  of  seasoning  in  waste- 
heat  humidifiers. 

The  face  brick  mixtures  consist  of  varying  proportions  of  Santa 
IMonica  red-burning  clay  and  a  number  of  varieties  of  Alberhill  clay. 
The  face  brick  production  of  this  plant  is  the  second  largest  in  the 

*  G.  Ray  Boggs,  private  communication,   December   S,   19".7. 


102  DIVISION  OF  MINES  AND  MINING 

Gladding,  McBean  organization.  A  wide  range  of  colors  and  textures 
are  ])rodnced. 

Quarry  tile  are  Jiaiul  made  from  mixes  similar  to  those  used  for  face 
brick,  and  are  produced  in  a  wide  range  of  red  colors.  The  product  is 
knoAvn  as  'Palacio'  tile. 

Practically  all  of  the  roofing  tile  produced  by  the  Southern  division 
and  approxinuitely  60%  of  that  manufactured  by  all  of  tlie  comi)any's 
l)lants  is  made  at  the  Los  Angeles  plant.  Both  machine  and  hand  made 
tile  are  produced.  The  laboratory  is  constantly  experimenting  on  new 
glazes  and  body  mixes,  and  many  distinctive  effects  have  been  produced. 

The  jilant  is  well  equipped.  Practically  all  labor  is  ])erformed 
mechanically  and  all  moving  of  material  is  done  by  motor.  There  are 
25  kilns,  divided  as  follows :  thirteen  round  down-draft  kilns,  four  terra 
cotta  muffle  kilns,  and  eight  rectangular  mufflle  kilns  for  enamel  work.. 

Santa  ^Monica  Plant:  Colorado  Avenue  and  Twenty-fifth  Street, 
Santa  Monica.  Formerly  owned  by  the  Los  Angeles  Pressed  P)riek 
Company.  The  products  are  roofing  tile,  hollow  tile,  flue  lining,  chim- 
ney pipe,  quarry  tile,  and  brick. 

Most  of  the  clay  used  is  mined  at  the  plant,  which  also  supplies  a 
large  quantity  of  clay  for  the  Los  Angeles  ])lant.  The  ])roi)erty  includes 
45  acres  of  clay  land.  The  deposit  is  similar  to  that  in  use  by  other 
manufacturers  in  this  area,  including  the  Western  Brick  Co.,  the 
Simons  Brick  Co.,  and  the  Santa  Monica  Brick  Co.  On  the  Gladding, 
McBean  jiroperty  the  clay  is  from  10  to  36  feet  thick,  dii)ping  north- 
westward, and  increasing  in  depth  in  that  direction,  presunuibly  under- 
lain by  gravel.  Sample  No.  61  was  taken  from  the  stock  ])ile  in  the 
])lant,  and  is  an  index  of  the  type  of  material  mined  by  this  company 
and  others  in  the  district.     The  test  results  are  on  page  341. 

All  products  are  made  by  the  stiff-mud  process,  on  auger  machines. 
The  quarry  tile,  known  as  'Promenade'  tile,  is  made  in  a  wide  variety 
of  red  tones,  with  here  and  there  a  purplish  to  greenish  hue. 

Twelve  round  down-draft  kilns  are  operated. 

Bibl:  Bull.  88,  ]).  214  (L.  A.  P.  B.  Co.),  and  p.  217  (Western  Art 
Tile  Works  (now  the  Tropico  plant).  Prel.  Rejit.  7,  i)p.  53-56  (Los 
Angeles  Pressed  Brick  Co.),  and  pp.  56-57  (Pacific  Minerals 
and  Chemical  Co.,  now  the  Tropico  plant). 

Tropico  Plant  :  Located  in  Glendale.  This  plant  was  started  in 
1902  as  the  Pacific  Art  Tile  Company,  the  first  factory  of  its  kind  west 
of  the  Rocky  Mountains.  After  several  reorganizations,  the  plant  was 
eventually  ac(|uired  by  Gladding,  McBean  &  Com])any  and  in  1922 
the  name  was  changed  to  its  present  form.  The  ]irincipal  products 
of  the  plant  are  sewer  pipe,  flue  lining,  architectural  terra  cotta,  and 
faience  tile. 

Sewer  Pipe:  Tlie  sewer  pipe  mixture  contains  red-burning  common 
clay  from  Santa  Monica  (sam])le  No.  61,  p.  341),  Emsco  red  (sample 
No.  72,  p.  328),  and  one  or  more  other  clays  from  various  sources.  The 
clay  is  prejmred  by  dry  pan  and  inig-mill,  shaped  in  power-driven 
('steam)  ])resses,  dried  on  slatted  floors,  and  fired  in  down-draft  bee- 
hive kilns,  fired  with  gas  up  to  1100-1300°  P.,  and  finished  to  cone  03, 
1980^  F.,  with  oil.  The  smaller  pipe  is  set  two  lengths  high,  and  requires 
a  firing  schedule  of  88  to  100  hours.'    The  larger  pipe  is  set  three  high, 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  103 

and  r('(|uiiv.s  a  12()-lionr  firiii":  schedule.  The  total  kiln  turnover  is 
10  to  11  days.  Thirty-two  kilns  are  in  u.se  for  sewer  pipe  and  flue 
lining,  each  with  a  capacity  of  approximately  40  tons. 

Flue  Linin<i':  Tlie  ])rincipal  inj^redicnt  of  the  flue  liniuii'  mixture  is 
the  white  Enisco  clay   (sample  No.  70,  j).  272). 

Terra  Cotta  :  Tho  architectural  terra  cotta  output  of  tliis  i)hint  is 
not  lar<i-e  at  jire.sent,  at  least  not  of  the  order  of  majrnitude  of  the  output 
at  the  Lincoln,  Placer  County,  ])lant  of  the  com|)any.  Essentially  the 
same  terra  cotta  mixtures  are  used  at  Trojjic')  as  at  Lincoln,  the  Lincoln 
clay  (sample  No.  157.  p.  ;504)  beinii'  shii)pe(l  to  Tropico  for  the  purpose. 
The  terra  cotta  mixture  is  prepared  by  dry  pans  and  pu^'  mills,  fol- 
lowed by  seasoninii'  in  humidified  rooms  for  at  least  24  hours  before 
l)ressing'.    Six  kilns  are  in  use  for  terra  cotta,  firinp:  to  cone  3  to  5. 

Tile:  The  faience  tile  is  nuide  by  dry  pressing  a  buff-burnin*;  body 
similar  to  the  terra  cotta  mixture,  biscuited  at  cone  4,  and  glost  at 
cone  05  and  OG.  The  body  is  mixed  and  ground  in  dry  pans,  and  shaped 
in  screw  i)resses,  formerly  operated  by  hand,  but  now  entirely  su])- 
planted  by  power  driven  presses.  At  the  time  of  visit,  July,  1925,  5 
bee-hive  kilns  were  in  use  for  tile.  The  biscuit  kilns  Avere  operated  on 
the  same  schedule  as  the  terra  cotta  kilns,  rerpiirinc'  100-110  hours 
firing,  while  the  glost  kilns  operated  on  a  20-hour  firing  schedule.  The 
glost  kilns  u.se  oil  exclusively.  A  small  tunnel  kiln  for  tile  has  since 
been  installed  in  order  to  secure  more  uniform  results,  and  to  decrease 
the  time  cycle. 

Miscellany:  This  j)lant  is  continually  progressing,  and  various 
improvements  and  economies  arc  being  added  from  time  to  time, 
^lechanical  handling  of  materials  is  in  use  wherever  it  is  economic. 
The  i)resent  system  of  handling  the  ware  is  on  hand  trucks,  running 
on  tracks,  in  the  sha])ing  and  glazing  departments.  A  gasoline  ti'actor 
is  used  for  kiln-yard  haulage.  Eecording  pyrometers  with  base  metal 
cou])les  are  used  for  temperature  control  of  the  kilns. 

A  laboratory  is  maintained  to  aid  in  the  development  of  terra 
cotta  glazes  and  bodies. 

Bibl:  Cal.  State  Min.  liur.  P.uU.  No.  38,  p.  217  (Western  Art 
Tile  Works)  ;  Prel.  Kept.  No.  7,  p.  56  (Pacific  Minerals  and 
Chemical  Co.). 

Glohe  Tile  and  Porcelain  Works.  P.  C.  Boving  (formerly  of  the 
Pomona  Tile  Com])any),  president  and  general  manager.  This  plant 
was  established  in  1927  for  the  manufacture  of  ceramic  floor  tile.  The 
plant  has  15,000  square  feet  of  floor  space,  and  the  capacity  is  3000 
s(puire  feet  of  tile  per  day.^ 

H  d:  H  Tile  Company.  Ord  Hagerman  and  V.  K.  Halieman.  Rej)- 
resented  by  C.  P.  Johnson,  Arcade  Building,  Los  Angeles.  This  com- 
pany was  organized  in  1927  with  a  capitalization  of  $30,000,  to  produce 
ceramic  tile."    Further  details  are  lacking  at  this  writing. 

Italian  Terra  Cotta  Co.  W.  H.  Robinson,  owner.  Office  and  plant 
at  1149  Mission  Road,  Los  Angeles.  This  is  claimed  to  be  the  only  plant 
on  the  Pacific  Coast  exclusively  engaged  in  the  manufacture  of  sculp- 
tured terra  cotta  garden  pieces. 

'  day-Worker,    Xovember.    1926,    p.    390. 
=  Clay-Worker,  August,   1927,  p.  123. 


104  DIVISION  OF  MINES  AND  MINING 

The  bodies  are  made  from  Alberhill  pink  mottled  (sample  Xo.  7,  p. 
o28)  and  hill  blue  (sample  Xo.  9,  p.  287),  and  some  Santa  ^loniea  clay 
(sample  Xo.  61,  p.  341),  which  produce  a  red  body  when  fired.  A  slip 
f^laze,  lifjht  brown  in  color,  is  used  on  some  pieces.  The  clays  are  pre- 
])ared  by  dry-pan  <>rindinsr  followed  by  a  puij-mill.  After  sufficient 
seasouinp-,  the  pieces  are  shaped  by  hand  pressing  in  plaster  molds  and 
air  dried  before  firing.  A  gas-fired  round  down-draft  kiln  is  used 
for  firing,  the  heating  schedule  ranging  from  68  to  72  hours. 

]\Iany  of  the  models  are  imported  from  Spain  and  Italy.  The 
market  for  the  products  is  not  confined  to  the  Los  Angeles  district, 
as  the  artistic  value  of  the  ware  has  often  imi)ressed  visitors  from 
other  sections  of  the  United  States,  and  many  pieces  have  been  shipped 
to  the  eastern  and  middle  western  states. 

Bibl:  Cal.  State  Miu.  Bur.  Prel.  Kept.  Xo.  7.  ]).  51. 

K.  &  31.  Pottery.  M.  C.  Myers,  president.  Oi^ice  and  plant  at  2318 
East  Fifty-second  Street,  Los  Angeles.. 

This  pottery  makes  stoneware  from  Alberhill  clays,  using  the  E-101, 
and  the  hill  blue  (sample  X^o.  11,  p.  257,  and  9,  p.  2S7)  varieties.  Ollas 
are  also  made  from  the  pink-mottled  clav  from  Alberhill  (sample  No. 
7.  p.  328). 

The  stoneware  is  made  by  turning  and  the  glaze  is  applied  to  the 
dried  ware  before  firing. 

The  plant  is  equipped  with  three  round  down-draft  gas-fired  kilns, 
25  feet,  22  feet,  and  15  feet  in  diameter,  res]iectively.  The  annual 
wholesale  value  of  the  product  is  nearly  $60,000. 

Bibl :  Cal   State  Min.  Bur.  Prel.  Kept.  Xo.  7,  p.  51. 

K  and  K  Brick  Company.^  0.  J.  Cubach,  president;  II.  D. 
Simons,  secretary.  Office.  801  ^Merchants  X'ational  Bank  Building.  Los 
Angeles.  This  company  owns  a  38-acre  property  in  Bishop  Canyon, 
Los  Angeles,  and  manufactures  common  brick. 

The  deposit  consists  of  blue  and  gray  plastic  shale,  10  to  20  feet 
thick,  underlying  from  two  to  five  feet  of  adobe  soil  and  gravel.  The 
clay  is  mined  by  hand  methods  in  an  open  cut,  and  is  transported  to 
the  plant  in  small  cars. 

The  stiff-mud  process  is  used.  The  plant  is  equipped  with  a  dry  pan, 
screens,  pug-mill,  and  a  Kaymond  auger  machine,  with  a  wire  cutter. 

The  brick  are  dried  in  open  drying  sheds,  and  are  fired  in  six  open 
field  kilns.     Both  natural  gas  and  oil  are  used  as  fuel. 

The  plant  o]>erates  throughout  the  year  and  35  men  are  employed. 
Power  is  suii]ilied  by  a  250-h.p.  boiler.  The  rated  capacity  of  the  plant 
is  75,000  brick  per  day. 

Bibl :  State  Min.  Bur.  Prel.  Kept.  7,  p.  51. 

La  Cal  Tile  Company.  Val  Alden  and  Kittridge  streets.  Van  X'uys. 
A  recent  report-  states  that  this  company  was  building  a  plant  on  the 
above  site,  at  a  cost  of  $70,000.  Further  details  are  lacking  at  this 
writing. 

Lindennan  tf-  Decker  Company.'^     Address,  Lomita.     This  is  a  firm 


^  Data  .supplied  by  W.  B.  Tucker,  district  mining  engineer,  November,  1927. 
=  Clay-W' orker,  March,  1926,  p.  207. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  105 

of  general  eontractoris  who  o\vii  a  lO-aere  proi)erty  at  Harbor  City 
that  is  now  under  lease  to  Mexicans,  who  are  manufacturing  hand-made 
i-oofing  tile. 

The  deposit  consists  of  10  to  15  foot  of  rod  clay,  overlain  by  one  to 
to  two  feet  of  gravel.  Hand  methods  of  mining  are  used,  and  the  clay 
is  delivered  to  the  tile  plant  bj^  a  horso-drawn  dump-cart.  The  clay  is 
l)repared  and  the  tile  shaped  by  hand.  Drying  is  done  in  tlie  open  aii-. 
A  round  gas-fired  kiln  is  used  for  firing. 

Long  Beach  Brick  Companji.^  H.  A.  Ilavnor,  president;  H.  C.  Arm- 
strong, secretary.  Office  at  154  Elm  Street,  Long  Beach.  The  co)npany 
owns  a  10-acre  property  at  Harbor  City,  and  manufactures  common 
brick. 

The  deposit  consists  of  rod  clay,  10  to  20  feet  thick,  covered  by  a 
maximum  of  two  feet  of  gravel.  The  clay  is  mined  b.y  scrapers,  and  is 
transported  to  the  plant  by  belt  conveyors  and  Ford  trucks. 

The  equipment  includes  a  dry  pan,  elevators,  screens,  American 
anger  machine,  and  wire  cutter.  Drying  is  done  in  o]ion-air  drying 
sheds.  Rope  conveyors  are  used  to  transport  the  brick  to  and  from  the 
drying  ,vard. 

Six  oi)en  field  kilns,  firod  with  natural  gas,  are  used.  The  ])lant 
usually  operated  during  ton  months  of  the  year,  employing  25  men. 
Electric  power  is  used,  the  installed  cai)acity  being  200  h.p.  The  rated 
capacity  of  the  plant  is  45,000  brick  per  8-hr.  day. 

Bibl :  Cal.  State  :\[in.  Bur.  Prcl.  Kept.  7,  p.  51. 

Los  Angeles  Brick  Co.  A.  A.  Conger,  president;  E.  W.  ]\Iurphy, 
vice  president ;  Henry  Prussing,  secretary ;  Gustav  Larsen,  director  in 
charge  of  operations;  W.  C.  Roordan,  director  in  charge  of  sales. 
Home  office,  1078  ^Mission  Road,  Los  Angeles. 

This  company  owns  and  operates  three  common-brick  and  hollow- 
tile  yards  in  the  Los  Angeles  district,  and  has  recently  built  a  plant 
at  Alberhill  to  manufacture  tile,  fire  brick,  and  other  ])roducts  (see 
under  Riverside  County,  p.  174)  from  clays  mined  on  their  own  pro]i- 
erties,  acquired  through  the  purchase  of  the  holding.s  of  the  California 
Clay  IManufacturing  Company. 

The  Los  Angeles  brick  yards  are  the  ^lission  Road  ]ilant,  at  the 
corner  of  ^Mission  and  jMarengo  streets,  near  the  County  Hospital;  the 
Chavez  Canon  plant,  in  Chavez  Cafion,  west  of  Adobe  street;  and  the 
Seventh  Street  plant,  at  East  Seventh  Street,  on  the  corner  of  Utah 
Street. 

^IrssTOX  Road  Yard:  This  property  comprises  15  acres.  The  clay 
is  a  surface  material  from  25  to  30  feet  thick,  underlain  by  five  or 
six  feet  of  sand.  Common  brick  only  are  made  at  this  plant,  using 
the  soft-mud,  sand-mold  process.  The  brick  are  air-dried,  then  fired 
in  ojien  field  kilns,  using  gas  as  fuel.  The  average  daily  capacity  of 
the  yard  is  80,000  brick.  A  Hoffman  continuous  kiln,  fired  with 
coal  screenings  was  formerly  in  use,  but  has  been  dismantled.  Rope 
conveyors  are  used  to  deliver  tlie  brick  pallets  from  the  ]U'esses  to  the 
drying  yard. 

Chavez  Caxon  Yard:  This  is  a  26-acre  property.  The  clay  is  a 
thin-bedded  Puente   (Lower  Miocene)  shale,  forming  a  bank  over  100 

'Data  supplied  by  W.  B,  Tucker,  district  mining  engineer,  November,   1927. 


106 


DIVISION  OP  MINES  AND  MINING 


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CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  107 

feet  lii^li,  and  dipping:  southward  into  the  hill.  Tiie  individual  beds 
of  shale  vary  from  a  very  fine-.trrained  plastic  clay,  to  a  sand,  the 
different  phases  being  ])resent  in  such  jn-oportions  as  to  make  an 
excellent  material  for  brick  and  hollow  tile.  The  clay  is  mined  by  a 
team  and  scra])er,  dumped  into  a  hoi)per,  delivered  to  a  ear,  which 
is  hauled  up  into  the  ])lant  by  an  electric  hoist.  The  clay  is  ground 
in  a  dry  pan,  and  fed  by  belt  conveyors  to  ])Ug-mills  and  auucr  machines. 
The  bricks  are  dried  in  driers  heated  with  steam  from  auxiliary  boilers. 
Firing  is  done  in  open  field  kilns,  with  gas  fuel.  The  capacity  of  the 
plant  is  80,0()()  brick  and  100  tons  of  hollow  building  tile  per  day. 

Seventh  Street  Yard:  This  yard  is  12  acres  in  area.  The  clay 
belongs  to  the  upper  ])ortion  of  the  Boyles  Heights  Terrace  formation. 
The  soft-mud  ])roeess  was  used,  followed  by  air  drying,  and  firing  in 
open  field  kilns.  It  is  i)robable  that  this  i)roperty  Avill  be  sold,  as 
it  has  become  too  valuable  for  industrial  i)roi)erty  to  Avarrant  its 
continuance  as  a  brick  yard. 

IJibl:  Cal.  State  Min.  Bur.  Prel.  Kept.  No.  7,  p.  52. 

Malihu  P(jfttries.  Owned  and  operated  by  the  ]\Iarblehead  Land  Co. ; 
R.  B.  Keeler,  plant  manager,  P.  O.  Box,  518,  Santa  Monica.  The  plant 
is  on  the  Coast  highway,  north  of  Santa  Monica.  The  products  of 
the  plant  are  plain  and  decorated  wall  tile,  made  from  a  terra  cotta 
body.     A  vieAV  of  the  plant  is  given  on  ])hoto  No.  16. 

A  variety  of  clays  are  used,  including  a  number  of  clays  from  the 
]\Ialibu  Ranch,  some  Alberhill  clays,  and  Engli.sh  ball  clay.  The  mixes 
are  prepared  by  grinding  in  a  4-ft.  dry  pan,  elevating  to  a  bin,  screen- 
ing, and  ]iug-milling.  followed  by  six  weeks  ageing.  ]Most  of  the  tile 
are  shai)ed  in  a  ^fuller  tile  auger,  but  some  are  liand-i)ressed  in  plaster 
molds.    Saggers  and  tile  setters  are  made  at  the  plant,  by  hand. 

A  Carrier  drier,  oi>erating  on  an  18-hour  cycle,  is  used  for  drying 
the  tile.     The  saggers  and  setters  are  dried  in  the  open. 

Three  up-draft  kilns  are  in  use.  On  biscuit  firing,  10,000  sq.  ft.  of 
tile  can  be  loaded  per  kiln,  and  the  entire  firing  cycle  takes  one  week. 
The  finishing  tem])erature  is  2300''  F.,  which  is  reached  in  96  hours 
fi-om  the  start  of  firing.  On  glost  firing,  each  kiln  holds  5000  sq.  ft.  of 
tile,  the  finishing  temperature  is  1600°  F.,  the  firing  occupies  48  hours, 
and  the  entire  cycle  takes  four  days.  Normally,  one  kiln  is  on  biscuit 
firing,  one  is  on  glost  firing,  and  the  third  is  used  for  either,  according 
to  conditions.     The  kilns  are  fired  with  oil,  atomized  by  air. 

Mission  Brick  Companij.^  ]Mrs.  A.  E.  L.  Anderson,  755^  Santa 
]\Ionica  Boulevard,  Los  Angeles,  owner.  Joseph  F.  Reutera,  manager. 
Office  and  plant  at  6140  Scpulveda  Boulevard,  Van  Nuys.  The  product 
of  the  plant  is  common  red  brick.  The  i)roperty  consists  of  five  acres 
of  land,  containing  a  bed  of  red  clay  from  5  to  20  feet  thick,  overlain 
b\-  from  one  to  two  feet  of  soil.  Mining  is  done  in  an  open  pit,  using 
scrapers  which  are  hauled  by  a  Fordson  tractor  to  a  hopper  which  feeds 
a  belt  conveyor  delivering  to  a  bin  at  the  plant.  The  soft-mud  process 
is  used.  The  plant  is  equipped  Avith  a  pug-mill  and  a  Quaker  brick 
]:>ress,  Avhich  has  a  capacity  of  20,000  brick  ])er  day.  The  brick  are 
dried  under  sheds,  to  which  they  are  transported  in  hand  trucks. 


'  Data  supplied  by  W.  B.  Tucker,  district  mining  engineer,  December,   1927. 


108 


DIVISION  OP  MINES  AND  MINING 


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CLAf  RESOURCES  AND  CERAlSflC  INDUSTRY  109 

Two  ji:a.s-fired  field  kilns  arc  used.  liavin<;'  a  eai)ac-ily  of  50,()()()  bricks 
each.  Electric  power  is  used  in  llic  j>lant,  the  installed  capacity  being 
60  h.p.  Twenty  men  are  employed  (luring  llic  operatinjr  season,  whicli 
is  usually  four  months. 

Mission  China  Conijxinn.  Victor  Ki'enior,  i)residcnt ;  Jas.  Tiffany, 
manager.  General  offices  at  .3121  W.  Third  Street,  Los  Angeles.  Plant 
at  652  S.  Griffin  Avenue.  Tiiis  ])lant  has  been  manufacturing  semi- 
jiorcelain  hotel  and  dinner  ware  for  a  number  of  years.  The  raw 
materials  in  use  are  P]uglisli  china  and  ball  clay,  Edgar  (Florida) 
kaolin,  and  California  feldspar  and  silica. 

The  body  mix  is  prepared  by  screening  through  150-mesh,  blunging, 
filter-pressing,  and  pugging.  ]Most  of  the  ware  is  shaped  by  jiggering, 
but  casting  is  used  on  the  more  complicated  shapes.  Steam  drivers 
are  used,  operating  on  a  12-hour  cycle.  Saggers  arc  molded  by  hand  at 
the  plant. 

The  biscuit  ware  is  fired  in  two  17-ft.  6-in.  up-draft  kilns,  to  a  finish- 
ing temperature  of  cone  S  (1225°  C),  requiring  55  to  60  hours.  The 
ware  is  then  dipped  in  glaze,  and  fired  in  two  16-ft.  glost  kilns  to  cone 
5  (1180°  C),  in  30  to  35  hours.  Two  days  are  required  for  cooling 
both  tyi^es  of  kilns.  The  paper  transfer  process  of  decorating  is  used, 
and  the  decoration  is  fired  on  at  cone  016  (735°  C).  Two  decorating 
kilns  are  in  use,  which  are  fired  in  12  to  14  hours,  the  entire  cycle 
requiring  30  hours.    All  kilns  are  fired  with  natural  gas. 

Fifty  men  and  women  are  employed  in  the  plant.  IMost  of  the  work 
is  i)aid  by  piece  rates,  which  are  the  same  as  those  established  in  eastern 
potteries. 

Pacific  Clinj  Ptuducts  Co.^  William  I^acy,  president;  Robert  Linton, 
vice  president  and  general  manager;  W.  R.  Faw^eett,  secretary- 
treasurer;  Wm.  McClintock,  general  superintendent.  Main  office,  1151 
South  Broadway,  Los  Angeles.  This  company  owns  and  operates  three 
factories  in  Los  Angeles  district  and  several  clay  proi)crties  in  River- 
side and  San  Diego  counties.  The  present  company  supersedes  the 
Pacific  Seiver  Pipe  Company  whicli  was  formed  some  years  ago  by 
consolidating  several  smaller  companies  situated  in  Los  Angeles,  Corona, 
and  Elsinore,  these  smaller  companies  having  started  business  around 
1880  to  1885. 

Clay  Properties  :  The  company  owns  and  operates  the  following  clay 
mines : 

Name  Shipping  point 

Douglas.s    Alberhill,   Riverside  County 

McKnight     Corona,   Riverside  County 

Wildomar    Wildomar,   Riverside  County 

'Hoist  Pit KIsinore,   Riverside  County 

Kelly  No.   1    Farr,   San   Diego  County 

'  The  company  owns  a  one-half  interest  in  this  property. 

In  addition  the  company  operates  under  lease  several  properties  in 
Orange  and  San  Diego  counties ;  also  owns  and  holds  in  reserve  for 
future  operations  five  additional  tracts  in  Riverside  and  San  Diego 
counties.  The  total  clay  lands  owned  outright  total  625  acres.  The 
bulk  of  the  clays  used  in  the  company's  plants  come  from  its  own 
mines,  although  some  are  purchased  from  the  Alberhill  Coal  and  Clay 

'  Description  prepared  by  the  company. 


110 


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CLAY  RESOURCES  AXD  CERAMIC  INDUSTRY  1 1 1 

Comp.iny,  the  Enisco  Chiy  ('oiiii);my,  and  llie  Lincoln  Clay  Products 
Company.  Many  difforont  clays  cntci-  into  tlic  manufacture  of  the 
various  products  nuide,  wliicli  include  s(>\ver  pipe,  electrical  conduit, 
face  brick,  enameled  brick  and  tile,  fire  brick  and  refractory  shapes, 
firechiy.  flue  lininji'  and  ^as  flues,  drain  tile,  stoneware,  earthenware 
water  coolers  and  other  articles. 

Plants:  Three  factories  are  operated  at  ])resent,  viz,  the  Lincoln 
TIeifrhts  plant.  Avenue  TAventy-six  and  ILunboldt  Avenue,  Los  Ang-eles; 
the  Slauson  plant.  Slauson  and  McKinley  avenues,  Los  Anii'eles,  and 
the  Los  Xietos  plant  on  the  eastern  edg'e  of  the  Santa  Fe  Sprinfi's  oil 
field.  The  plants  have  a  combined  cai)acity  of  over  90,000  tons  of  clay 
]n'oducts  per  year.  A  ])lant  at  Terra  Cotta,  near  Elsinore,  and  two 
l)lants  at  Corona  Avere  also  formerly  0])erated.  GeiU'ral  views  of  the 
Lincoln  Heights  and  the  Los  Nietos  i)lants  are  shown  on  photos  No.  18 
and  19. 

Lincoln  Heights  Plant  .-  J.  L.  Davies,  sui)erintendent.  This  factory 
was  built  about  1890  and  was  equi]>ped  to  manufacture  sewer  pipe, 
brick  and  stoneware.  At  ]iresent  it  com])rises  a  brick  department 
in-oducinji'  face  brick,  enamel  brick  and  tile,  fire  brick  and  refractory 
shapes  and  roofin<]:  tile ;  and  a  stoneware  department  making'  a  com- 
])i-ehensive  line  of  grey  earthenware,  ollas,  mixing  bowls,  etc. 

Clays  for  the  stoneware  are  selected  with  esjiecial  reference  to 
producing  a  body  as  dense  and  impervious  as  possible;  for  ollas,  or 
self-cooling  water  jars,  the  body  should  be  slightly  porous,  since  the 
cooling  comes  from  evaporation  of  water  which  percolates  through  the 
jar  to  the  outer  surface.  The  mixes  are  finely  ground  in  a  Raymond 
hammer  i)ulverizer,  the  dust  being  lifted  by  a  suction  fan  a  height  of 
10  feet  to  the  pug-mill  feeder.  The  pugged  clay  is  allowed  to  soak  in 
the  'sweating  room'  for  24  hours  or  more,  then  goes  to  the  jig  rooms 
where  there  are  9  potters'  wheels  suitable  for  making  all  kinds  of 
turned  ])ottery  up  to  a  12-gallon  jar.  The  ware  is  dried  in  steam- 
heated  dryers,  then  dipped  in  the  proper  glaze.  Some  of  the  stone- 
ware is  given  a  biscuit  firing  before  glazing,  but  most  of  it  is  made  at 
a  single  bui'ning.  using  a  slip  glaze  wliich  niatures  at  the  same  tem])era- 
ture  as  the  body.  The  stoneware  bodies  mature  at  about  cone  8,  and 
are  a  cream  or  light  yellow  color.  Saggers  made  at  the  plant  are  used 
for  some  of  the  ware,  chiefly  for  sup])ort.  but  as  much  ware  as  possible^ 
is  open  fired.  There  are  o  kilns  20  to  24  feet  diameter  used  for 
stoneware. 

The  brick  department  equipment  consists  of  3  dry  pans.  Hummer 
screens,  2  pug-mills,  2  auger  machines,  tAvo  14-brick  American  cutters, 
2  rejiresses,  2  humidity  di-yers  holding  40,000  brick  each,  an  ovei'head 
traveling  crane  Avith  clam  shell  for  clay  unloading,  2  electric  lift  trucks 
Avith  i)allets  for  handling  brick,  and  11  kilns  80  feet  diameter.  The 
cai)acity  is  40.000  brick  per  day. 

A  AucAv  of  the  clay  bins  and  unloading  crane  is  shoAvn  on  photo  No.  20, 
and  a  pug-mill,  auger  machine  and  cutter  is  shown  on  photo  No.  21. 

The  stiff-mud  brick — comprising  the  rough  and  smooth  texture  wire 
cut  face  brick  and  re-pressed  Avire  cut  fire  brick — are  dried  in  the 
humidity  dryers  in  42  hours.  About  6  days  are  required  for  the  firing, 
the  finishing  temperature  being  about  2100^.  Dry  press  brick  go 
directly  to  the  kilns  Avithout  preliminarA^  drying,  and  are  burned  to 


112 


DIVISION  OF  MINES  AND  MINING 


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CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


113 


about  2050^.  Enaincl  brick  are  made  on  biscuit,  or  bui'iied  ])ressed 
brick,  whicli  are  coated  with  enamel  slips  and  buiMied  a  second  time  to 
mature  the  glaze. 

A  variety  of  very  attractive  shades  of  red,  tan,  g'rey  and  other  colors 
is  made  in  the  wire-cut  brick.  Present  architectural  practice  favors 
eombininji-  ditferent  shades  and  colors,  following  the  impressionistic 
idea,  and  tliese  combinations  are  ])roved  very  effective  in  lending 
distinction  to  face-brick  buildings.  The  Pacific  enamel  brick  is  in 
wide  deiiiaiid  and  is  ship|)ed  to  all  tlie  Pacific  Coast  states  as  well  as 
abroad. 

A  comph'te  line  of  fire  bi'ick  and  i-clVactorics  is  also  inanufactui'ed. 
Three  grades  of  standard  fire-brick  are  made,  with  softening  points  of 


Photo  No.   20.     Clay  bins   and   unloading  crane,   Lincoln   Heights   plant,    Pacific 
Clay  Products  Co.,  Los  Angeles.      (Photo  by  courtesy  of  the  company.) 

about  3200°  F.,  3100°  P.  and  3000°  F.,  respectively.  The  highest 
grade  brick  is  hand  molded,  the  others  made  on  the  auger  machine  and 
repressed.     They  are  burned  to  about  2500"  F. 

Roofing  tile  are  also  made,  using  a  combination  Hummer  machine. 
They  are  dried  on  waste  heat  drying  floors  and  burned  in  the  brick 
kilns. 

Over  20  different  clays  are  used  at  this  jilant,  coming  from  Riverside, 
Orange,  San  Diego,  Los  Angeles,  and  Placer  counties.  The  plant  site 
comprises  over  six  acres,  and  lies  between  main  lines  of  the  Santa  Fe 
and  Union  Pacific  railroads,  having  sidings  from  each.     The  plant  is 

8 — 54979 


114 


DIVISION  OP  MINES  AND  MINING 


equipped  to  use  either  natural  gas  or  fuel  oil.     Machinery  is  all  motor- 
driven.     About  130  men  are  employed. 

The  company's  laboratories  are  located  at  tliis  plant  and  are  fully 
equipped  for  chemical  and  testing-  work.  A  high  temperature  testing 
kiln  capable  of  heating  up  to  3400''  F.,  is  used  for  testing  fire  brick. 
Routine  testing  for  color  and  shrinkage  is  regularly  carried  on.  All 
kilns  are  equipped  with  pyrometers  which  are  used  for  control  in 
connection  with  Orton  standard  cones. 

Los  NiETOS  Plant  :  Cecil  V.  McClintock,  superintendent.  The  Los 
Nietos  factory  is  the  largest  and  newest  of  the  plants,  and  is  situated 


I'HOTO    No.    21.      Pug-mill,    auger    machine    and    cutter,    Lincoln    Heights    plant, 
Pacifle  Clay  Products  Co.,  Los  Angeles.     (Photo  by  courtesy  of  the  company.) 


on  a  46-acre  tract  on  the  edge  of  the  Santa  Fe  Springs  oil  field.  It  is 
a  thoroughly  modern,  well-arranged  plant.  Sewer  pipe  is  the  principal 
product,  but  electric  conduit  segmental  sewer  blocks  and  lining  blocks, 
drain  tile  and  flue  lining  are  also  made. 

The  plant  makes  sewer  pipe,  electric  conduit,  roofing  tile,  drain 
tile,  flue  lining  and  gas  flues.  Clays  are  shipped  in  from  Riverside  and 
San  Diego  counties  and  some  clay  mined  on  the  premises  is  also  used. 

The  equipment  comprises  three  9-ft.  American  dry  pans,  2  pulver- 
izers, gravity  screens,  four  8-ft.  American  wet  pans,  one  14-ft.  pug-mill. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


115 


3  sewer-pipe  presses,  1  aiip-er  machine,  and  .'}()  riituhu-  down-draft  kilns 
30  and  34  feet  dianietei-.  Some  of  the  dry  and  wet  pans  are  sliown  on 
])hoto  No.  '22,  and  one  of  llie  s(>wei'-pipe  presses  is  sliown  on  i)hoto  No. 
23.  The  dryinji'  Hoor  is  220  x  !t20  ft.  and  is  shown  on  photo  No.  17. 
There  is  a  \vell-equi|)i)('d  machine  shoj)  and  testing  ])laii1  foi-  sewer  i)ipe. 
Steam  is  fni'nislied  from  two  250-h.p.  IJaheock  and  Wik'ox  boilers,  with 
three  150-h.p.  luhuhir  hoik^rs  as  stand-by.  Excepting  tlie  steam-driven 
sewer-pipe  presses  all  e(inipment  is  driven  by  electric  motors.  Natural 
gas  and  oil  are  both  used  for  fuel. 

Clays  are  shipped  in  from  Riverside  and  San  Diego  counties  and 
used  in  connection  with  red  shale  mined  on  the  i)remiscs.  The  clay 
track  is  elevated  above  the  storage  bins  so  that  the  clays  are  dumped 


Photo   No.    22.     Dry  pans   and    twin    wet   pans,    T^os    Nietos   plant,    Pacific   Clay 
Products  Co.,  I^os  Angeles  Couiily.      (Photo  by  courtesy  of  the  company.) 


directly  from  the  ears  at  minimum  cost.  Some  of  them  require  fine 
grinding  which  is  done  by  regrinding  the  oversize  from  the  screens  in 
pulverizers  of  the  squirrel-cage  type. 

The  drying  room  is  equipped  with  steam-heating  pipes  overhead  and 
underneath  the  floor,  affording  very  satisfactory  control.  From  2  to 
15  days  is  required  to  dry  the  ware,  depending  upon  the  size.  Firing 
time  varies  likewise  from  3  to  8  days.  The  bodies  mature  at  2100°  F. 
to  2200°  F.  The  salt  glazing  is  done  during  the  last  two  hours  of  the 
firing,  i.  e.,  when  the  kiln  is  at  maximum  heat,  by  throwing  a  shovelful 
of  salt  into  each  fire-box  every  fifteen  minutes.  The  salt  volatilizes,  is 
carried  through  and  around  the  hot  pipe,  and  as  the  vapor  comes  in 


116 


DIVISION  OP  MINES  AND  MINING 


contact  with  the  clay  the  alkali  in  the  salt  combines  with  the  silica  of 
Ihe  clay  to  form  the  ^laze  on  the  surface. 

All  sizes  of  sewer  pipe  up  to  aiul  including  80-inch  are  made.  Seg- 
mental blocks  for  making  sewers  of  larger  size  are  also  among  the 
products.     The  plant  emi)loys  150  men. 

The  i)lant  is  served  by  both  Santa  Fe  and  Southern  Pacific  railroads, 
having  sidings  connecting  directly  with  each. 

Slauson  Avenue  Plant  :  Roy  Lacy,  superintendent.  The  Slauson 
Avenue  plant  was  built  about  1885.  It  is  located  on  a  tract  of  six 
acres  on  McKinley  Avenue  from  Slauson  Avenue  to  Fifty-third  Street. 
It  is  served  by  the  Santa  Fe  Railroad,  the  plant  sidings  connecting 


Photo  No.    23.     Sewer-pipe   press,   Los   Nietos   plant,   Pacific  Clay  Products  Co., 
Los  Angeles  County.      (Photo  by  courtesy  of  the  company.) 

with  the  tracks  on  Slauson  Avenue.  Equipment  consists  of  a  conveyor 
unloader  for  clay,  2  dry  pans,  pug-mill,  double-shaft  auger  machine, 
and  sewer-pipe  press.     There  are  seven  30-foot  kilns  and  one  28-foot. 

Pomona  Brick  Company.''  E.  G.  Stahlman,  president;  H.  F.  Stahl- 
man,  secretary.  Address,  Pomona.  This  company  owns  a  10-acre 
property  on  West  Ninth  Street,  Pomona,  and  manufactures  common 
brick. 

The  dei)osit  consists  of  red  sandy  clay,  8  to  20  feet  thick,  without  over- 
burden.    The  clay  is  loaded  by  a  small  steam  shovel  into  trucks. 

The  plant  equipment  includes  a  dry  ])an,  screens,  pug-mills,  and  a 

'  Data  supplied  by  W.  B.  Tucker,  district  mining  engineer,  November,  1927. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  117 

Potts  brick  pi'ess.      Tlie  brick  are  conveyed  to  a  (lryiii«i'  yard  on  rope 
conveyors.      Five  field  kilns,  fired  with  natural  ^as,  are  in  use. 

The  plant  operates  during  about  six  months  of  the  year,  and  employs 
14  men  during  that  jieriod.  About  IK^  h.p.  of  steam  ))ower  are  required. 
The  rated  capacity  of  the  jilant  is  ;W,0()()  brick  i)er  8-hi-.  day. 

Bibl:  Cal.  State  Min.  Bur.  Prel.  Kept.  7.  j).  58. 

Puinona  Tile  Manufacturin<i  ('oiiip(ni>i,  Tliird  and  Reservoir  streets, 
Pomona.  R.  J.  Scliroeder,  j^residt-nt  and  treasurer;  C.  V.  Svendsen, 
superintendent.  This  company  manufactures  ceramic  floor  and  wall 
tile,  using  Edgar  clay  from  Florida,  English  china  clay,  California  and 
Arizona  feldspar,  California  silica,  and  some  Santa  ^Monica  clay  where 
red-burning  bodies  are  re(iuired.  Albci-hiii  and  Lincoln  clays  are  used 
for  saggers. 

The  tile  are  shaped  in  hand-operated  dry  presses.  At  the  time  of 
visit.  July,  1925,  two  down-draft  kilns  were  in  opei'ation,  and  a  third 
kiln  for  increasing  the  capacity  by  HO'^f  was  under  construction.  Gas  is 
used  for  fuel,  with  oil  in  reserve.     The  kilns  are  fired  to  cone  11. 

The  plant  emj^loys  from  40  to  45  employees,  mostly  women  and  girls, 
Avho  do  the  Avork  of  packing  and  un])ackinu-  the  saggers,  cleaning  the 
tile  after  firing,  and  pasting  them  on  paper. 

Poxon  Pottery.  G.  J.  Poxon,  president ;  Earl  Lincoln,  foreman. 
Offices  2300  East  Fifty-second  Street,  Los  Angeles.  This  pottery  makes 
a  complete  line  of  plain  and  decorated  table  ware.  All  of  the  clays 
used  are  imported  from  England.  The  im])orts  amount  to  about  1000 
tons  per  year  of  ball  and  china  clay.  Feldspar  and  silica  of  the  best 
quality  are  obtained  from  various  sources  in  southern  California, 
mainly  from  Riverside  County. 

After  coarse-crushing  to  about  Y'  size,  the  silica  and  feldspar  are 
mixed  in  the  proper  ]n'0]iortion  with  the  clays,  and  the  grinding  is 
finished  in  a  wet  ])uli).  The  mix  is  tlien  passed  to  filter  presses  for  the 
removal  of  excess  moisture,  and  the  filter  cake  is  then  ready  for 
shaping. 

Power-driven  wheels  are  used  tliroughout  for  all  shapes  that  can  be 
made  mechanically.  After  shaping,  the  ware  is  dried  for  about  three 
hours  in  gas-heated  drying  rooms,  or  for  a  longer  time  in  the  factory 
atmosphere. 

The  biscuit  firing  is  done  in  gas-fired  kilns  at  a  temperature  of 
2300°  F.,  for  70  hours.  After  cooling,  the  ware  is  dipped  in  the 
glazing  material,  and  fired  for  30  hours  at  1800"  F. 

Some  of  the  decorating  is  done  by  the  paper-transferring  ])rocess, 
while  the  higher-])riced  ware  is  hand-decorated.  After  decorating,  the 
ware  is  fired  for  12  hours  at  about  1100=  F. 

Seven  gas-fired  kilns  are  in  use.  The  factory  produces  about  1500 
dozen  pieces  per  day,  and  employs  70  men  and  women. 

Some  ten  years  ago  this  plant  used  California  clays,  but  found  that 
the  English  clays  gave  better  results.  Kaolin  from  Hart,  San  Ber- 
nardino County,  has  been  used  recently,  but  is  said  to  be  too  variable. 
Clay  from  Amador  County  has  been  tested  with  good  results. 

In  1926,  the  company  built  a  new  plant  at  Slauson  and  Miles  ave- 
nues, in  Vernon.  It  is  understood  that  both  i)lants  will  be  operated, 
but  further  details  are  lacking  at  this  writing. 


118  DIVISION  OF  MINES  AND  MINING 

St.  Louis  Fire  Brick  and  Clay  Co.  Joseph  Mesmer,  president ;  A.  J. 
Mesmer,  superintendent.  Office  and  plant  at  2464  E.  Ninth  Street.  Los 
Angeles.  This  eompanj^  manufactures  fire  brick.  Practically  all  of 
the  clays  in  use  at  present  are  purchased  from  various  sources,  but  the 
company  owns  a  deposit  near  Corona  that  has  been  worked  at  various 
times  in  the  past.  The  principal  clays  in  use  are  the  select  main  tunnel 
(sample  No.  15,  p.  264)  and  west  blue  (sample  No.  23,  ]).  277)  from 
Alberliill ;  the  Emsco  pink  mottled  (sample  No.  71,  p.  278)  and  the  Lin- 
coln, No.  1-6  (sam])le  No.  146.  ]).  308).  Some  experiments  were  made 
with  the  Weiss  clay  from  Glen  Ellen,  Sonoma  County  (samples  No. 
194  and  195,  p.  262),  but  difficulties  were  encountered  in  securing  satis- 
factory stnength. 

Both  the  auger  and  hand-pressing  processes  are  in  use,  and  the  brick 
are  fired  in  three  down-draft  bee-hive  kilns,  and  two  rectangular  kilns, 
using  oil  as  fuel. 


"^o 


Bibl:  Cal.  State  Min.  Bur.  Prel.  Kept.  7,  p.  58. 

Santa  Monica  Brick  Company.'^  E.  A.  Douglas,  president;  F.  ^M. 
Taylor,  vice  president  and  treasurer.  Office  and  plant  at  Twenty-third 
and  Michigan  streets,  Santa  Monica.  The  company  owns  10  acres  of 
clay  land  and  manufactures  common  brick,  red  face  brick,  roofing  tile, 
and  red  floor  tile. 

The  clay  is  a  plastic,  red-burning  clay,  underlying  an  extensive  area 
from  which  numerous  other  manufacturers  in  the  Los  Angeles  district 
secure  clay  for  brick,  hollow  tile,  roofing  tile,  and  sewer  pipe  manufac- 
ture. There  is  no  overburden.  The  deposit  is  now  (1927)  being 
worked  by  a  power  shovel  against  a  45-ft.  bank,  but  the  height  of  the 
bank  may  be  increased  in  the  future  to  75  feet.  The  clay  is  trans- 
l)orted  to  the  plant  in  cars  operated  by  an  endless  cable  hoist. 

Tlie  plant  is  equipped  with  a  60-h.p.  24-in.  by  24-in.  American  dis- 
integrator, a  150-li.p.  American  auger  machine,  having  a  rated  capacity 
of  75.000  brick  per  day,  an  American  automatic  brick  cutter,  a  40-h.p. 
Pate-Koot-Heath  roofing-tile  auger,  having  a  rated  capacity  of  10,000 
tile  per  day,  and  a  hand-operated  roofing-tile  cutter,  in  addition  to  the 
necessary  elevating  and  conveying  equipment. 

A  hot-air  tunnel  drier  is  used,  which  operates  on  a  schedule  of  36 
hours.  Ten  up-draft  field  kilns  with  permanent  walls  are  used  for 
firing.  Both  natural  gas  and  steam-atomized  oil  are  used.  Normally, 
four  kilns  each  with  a  capacity  of  500,000,  are  used  for  firing  brick, 
five  kilns  of  15,000  capacity  each  are  used  for  roofing  tile,  and  one  kiln 
of  1000  sq.  ft.  capacity  is  used  for  floor  tile.  The  brick  are  water 
smoked  for  three  days,  fired  for  four  days,  and  allowed  to  cool  for  three 
(lays.  Drawing  and  setting  require  about  seven  days.  The  finishing 
temi)erature  at  the  end  of  the  firing  period  is  approximately  cone  07 
(975°  C,  or  1787°  F.).  The  tile  are  water  smoked  for  one  day,  fired 
for  three  days,  and  cooled  in  two  days.  One  day  is  sufficient  for  setting 
and  drawing. 

The  company  also  makes  liand-made  ]\Iission  roofing  tile,  which  are 
dried  in  the  open  air. 

The  plant  is  operated  throughout  the  year,  employing  60  men.  A 
total  of  350  h.p.  of  electric  power  is  installed  in  the  plant.     The  rated 

'  Data  supplied  through  the  courtesy  of  the  company. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  119 

c'aj)aeity  of  tl\e  plant  is  T.l.OOU  l)riek  and  40  .s(iuares   (lUU  square  ieet 
each)  of  roofin«r  tile  per  day. 

Simona  Brick  Co.  Walter  R.  Simons,  president ;  Robt.  P.  Isitt,  vice 
president ;  H.  B.  Howeth,  secretary ;  J.  T.  Crampton,  treasurer.  Office 
at  125  West  Third  Street,  Los  Angeles. 

Boyle  Plant:  The  r>oylo  i)lajit  of  the  Simons  company  occupies 
a  .^O-aere  ])roperty  at  1117  South  IJoyk'  Avenue,  on  the  east  bank  of 
the  Los  Angeles  River,  a  few  blocks  south  of  the  Seventh  Street  yard  of 
the  Los  Angeles  Brick  Co.  Tliis  plant  is  now  engaged  in  the  manu- 
facture of  roofing  tile  exclusively.  The  claj'  deposits  on  the  property 
have  been  worked  out  by  past  operations,  at  least  to  such  an  extent 
that  it  is  more  economical  to  ship  clay  to  this  plant  from  the  company's 
large  pit  at  Santa  ]\Iouica.  Tn  order  to  produce  the  wide  variety  of 
colors  demanded  by  the  trade  of  today,  varying  amounts  of  Emsco 
white  i)lastic  (sample  No.  70.  \).  272)  and  other  clays  fi-oin  the  Alberhill 
district  are  mixed  with  the  Santa  Monica  material.  Most  of  the  ware 
is  red,  and  the  mixture  for  this  ])ro(luet  contains  75%  Santa  Monica 
clay  and  25%  of  a  pink  burning  fire  clay,  such  as  Emsco  pink  mottled 
(sam])I('  Xo.  71,  p.  278).  Liglit  i)i]ik,  cream,  and  buff  tile  are  produced 
by  adding  \\\)  to  90%  of  a  light  burning  fire  clay. 

The  tile  are  formed  by  the  stiff-mud  process,  with  Mueller  machines. 
Drying  under  .sheds  requires  nearly  a  Aveek.  Firing  is  done  in  12 
down-draft  bee-hive  kilns.  The  lighter-colored  tile,  containing  more 
refi-actory  clay  than  the  i-ed  burned  variety,  are  fired  in  one  compart- 
ment of  a  double  rectangular  kiln,  the  dimensions  of  each  compartment 
being  6  ft.  by  20  ft.  by  8  ft.  A  temperature  of  2500°  F.  is  required, 
and  the  heating  period  occupies  three  days.  Kiln  slabs,  for  supporting 
the  tile  during  firing,  are  made  of  a  mixture  high  in  refractory  clays, 
and  are  fired  in  the  other  compartment  of  the  double  rectangular  kiln. 

Saxta  Monica  Plant:  This  plant  is  at  Colorado  Avenue  and 
Twentj'-sixth  .street,  Santa  jMonica.  The  property  consists  of  24  acres. 
The  clay  is  similar  to  that  on  other  properties  in  the  same  area ;  see 
under  Gladding,  McBean  and  Company,  Santa  Monica  Brick  Company, 
and  others.  The  soft-mud  process  is  u.sed  and  the  brick  are  fired  in 
oil-fired  field  kilns. 

Simons  Plant  :  The  Simons  ]ilant  is  advertised  as  being  the  largest 
plant  in  the  world  exclusively  devoted  to  the  manufacture  of  common 
brick.  It  is  situated  on  a  400-acre  tract  at  Simons,  on  the  main  line 
of  the  Santa  Fe  Railroad,  1 1  miles  northeast  of  Montebello  on  the 
Southern  Pacific  Railroad. 

The  clay  is  of  excellent  quality  for  the  manufacture  of  common  brick, 
and  occurs  in  a  superficial  bed  averaging  16  to  18  feet  in  thickness, 
underlain  by  fine  sand.  The  clay  is  mined  by  steam  shovel,  and  hauled  to 
the  ])lant  in  6-yard  cars  by  gasoline  locomotives.  Sixteen  soft-mud  ])ug 
mills  and  Potts  presses  are  arranged  in  units  of  two  machines  each  at 
such  positions  in  the  yard  as  to  provide  ample  room  for  drying  sheds 
l)laced  so  as  to  secure  the  mo.st  economical  trans])ortation  of  the  brick 
from  the  presses,  and  to  the  kilns.  The  brick  are  dried  in  from  7  to 
10  days,  depending  upon  the  weather,  and  are  fired  in  gas-fired  field 
kilns.    An  18-arch  kiln  will  hold  756,000  brick,  and  a  30-arch  kiln  hold'" 


120  DIVISION  OF  MINES  AND  MINING 

1,250,000.    Both  sizes  are  in  use,  tlie  choice  depending  on  requirements 
at  the  time  of  setting. 

The  total  capacity  of  the  yard  is  650.000  brick  per  day.  The  company 
has  jHirchased  a  townsite,  and  has  built  homes  for  renting  at  a  nominal 
rate  to  its  650  employees.  Recreational  facilities  are  provided,  and 
every  attempt  is  made  to  secure  a  permanent  force  of  satisfied 
employees. 

Sta7idard  Bricl'  Co.  J.  V.  Simons,  president ;  R.  G.  Simons,  vice 
president ;  H.  W.  Simons,  secretary.  OtBce  at  102  Stimson  Building, 
129  West  Third  Street,  Los  Angeles.  This  company  manufactures 
common  red  brick,  and  sewer  brick,  which  are  semi-vitrified  common 
brick.  Two  yards  are  operated,  one  at  Soto  and  Lugo  streets,  on  the 
southern  end  of  Boyle  Heights,  the  other  on  Eucalyptus  Street,  in 
Ingle  wood. 

Boyle  Heights  Plant  :  This  property  covers  8  acres.  The  material 
is  a  clay  loam,  15  to  18  feet  thick,  underlain  by  sand.  A  steam  shovel 
is  used  to  mine  the  clay  and  load  it  into  dump  wayons,  which  are  hauled 
to  the  di\y  pans.  The  brick  are  made  in  Potts  soft-mud  brick  machines, 
and  are  dried  in  air  under  sheds,  requiring  from  three  to  four  days. 
Three  or  four  gas-fired  field  kilns  are  maintained,  depending  upon  the 
demand.  The  brick  in  the  arches  are  carried  to  the  semi-vitrification 
point,  Avith  less  than  10 /V  absorption,  are  sorted  out  after  firing,  and 
sold  as  .sewer  brick.  The  firing  cycle  is  usually  five  and  one-half  days 
firing,  and  an  equal  time  cooling.    Mr.  Welldon  is  foreman. 

Ingle\vood  :  At  Inglewood  the  clay  is  of  much  the  same  character 
as  at  the  Boyle  Heights  plant,  containing  lenses  of  sand  and  fine  gravel, 
underlain  by  coarse  gravel.  The  same  brick-making  ])rocess  is  used 
here  as  in  the  Los  Angeles  yard.     Mr.  Paye  is  foreman. 

Bibl :  Cal.  State  Min.  Bur.  Prel.  Kept.  No.  7,  p.  62. 

Torrance  Bricl'  Contpanij.^  T.  H.  Reed,  president ;  V.  T.  Pullman, 
secretary.    Office  address,  Torrance.    This  company  operates  two  jilants. 

Plant  No.  1 :  This  plant  is  on  the  Plaza  del  Almo  Boulevard,  Tor- 
rance, and  produces  common  red  brick  only.  The  property  comprises 
15  acres,  consisting  of  a  30-ft.  bed  of  red  and  yellow  plastic  clay,  over- 
lain by  about  one  foot  of  soil.  The  clay  is  mined  by  scrapers,  which 
deliver  to  a  hopper  in  the  ])lant.  From  the  hopper,  the  clay  is  elevated 
by  a  bucket  elevator  to  rolls.  Tlie  roll  jiroduct  is  elevated  by  a  bucket 
elevator  to  wire  screens,  which  return  oversize  to  the  rolls  for  regrind- 
ing  and  deliver  undersize  to  a  pug-mill.  Tlie  pugged  clay  passes  to  an 
auger  machine,  ecpiipiied  with  a  wire  cutter.  The  capacity  of  the  auger 
is  60,000  brick  per  day. 

The  brick  are  transported  to  drying  sheds'  in  hand-trucks.  Four 
open  field  kilns,  fired  with  natural  gas.  are  in  use.  The  kilns  have  a 
capacity  of  750,000  brick  each.  The  plant  operates  throughout  the 
year.  Electric  ])ower  is  used,  the  installed  capacity  being  105  h.p. 
Thirty  men  are  employed. 

Plant  No.  2.  This  plant  is  at  Graves  Avenue  and  Jackson  Street, 
^lonterey  Park.      Common  brick,  hollow  tile,  and  red  face  brick  are 

'  Data  supplied  by  W.  B.  Tiiokcr.  cli.vtrict  mining:  engineer,  December,  1927. 


(LAY  RESOURCES  AND  CERAMIC  INDUSTRY  121 

produced.  The  proi)erty  consists  of  20  acres  of  clay  shale,  from  20  to 
30  feet  thick.  Tlie  ca))acity  of  the  plant  is  60,000  brick  ])er  day,  or 
its  equivalent  in  other  ware.  Electric  power  is  used,  the  installed 
capacity  bein^r  120  li.p.     Forty  men  are  employed. 

Tudor  Art  Tile  Company.  H.  C.  Hill,  C.  J.  Biddle,  T.  P.  Cook,  and 
Geo.  Skee,  owners,  deo.  Skee,  suj)erintendent.  Office  address,  1204 
Lane  iIort<>a,ue  Building,  Los  Anjieles.  Plant  at  5848.2  I^anta  Pe  Ave- 
nue, Los  Antjeles.  This  company  manufactures  faience  tile  and  inserts, 
usino-  Alberhill  clay.  All  special  shapes  are  hand-molded  in  plaster 
molds,  and  an  au<i'er  machine  is  used  for  standai'd  tile  sha])es.  Two 
yas-tired  kilns  are  used.  One  is  a  rectangular  semi-down-draft,  6-ft.  by 
8-ft.  by  6-ft.,  fired  to  cone  01  (1145°  C.)  for  biscuiting,  and  the  other 
is  a  rectangular  muffle  glost  kiln,  5-ft.  bv  6i-ft.  bv  12-ft.,  fired  to  cone 
02  (1125°  C). 

Clay-Worker  rcj^orts'  the  organization  of  the  Tudor  Potteries,  Inc., 
with  a  capitalization  of  $50,000,  by  C.  J.  Piddle  and  M.  L.  Vincent. 
No  further  information  was  available  at  the  time  of  going-  to  press. 

The  Vifrefrax  Company.^  Harvey  M.  BroAvn,  president;  Geo.  W. 
Clemson,  vice  president;  C.  V.  Knemeyer,  secretary;  Ralph  W.  Brown, 
treasurer  and  general  manager;  Thomas  S.  Curtis,  director  of  research. 
Office  and  plant  at  5100  Pacific  Boulevard,  Los  Angeles. 

This  company  manufactures  a  broad  line  of  ceramic  materials  for 
the  porcelain,  white-ware,  and  electrical  isulator  trade,  as  well  as  super 
refractories  in  the  form  of  prepared  grains,  cements  and  finished  raw 
materials,  together  with  a  line  of  finished  refractory  brick  and  shapes 
for  the  glass  industry. 

The  company  maintains  an  extensive  research  and  development 
laboratory  for  fundamental  investigations,  as  well  as  a  control  labora- 
tory for  physical  and  chemical  control  of  its  regular  products. 

In  Imperial  County,  near  Ogilby,  California,  the  company  owns  and 
operates  an  immense  deposit  of  cyanite,  which  forms  the  principal  raw 
material  for  its  mullite  line  of  refractories  and  ceramic  materials.  In 
addition,  the  eomany  has  under  long  contract  abundant  su))idies  of 
aluminum  o.xide  at  ]\Iarysville,  Utah;  high  alumina  clays  from  the 
Alberhill  and  Santa  ^largarita  Ranch  deposits;  and  contract  control  of 
what  is  believed  to  be  the  purest  magnesium  oxide  resources  in  the 
United  States. 

The  mullite  products  of  the  company  constitute  its  most  important 
line.  The  material  is  manufactured  in  several  grades,  one  of  which  is 
made  esjiecially  for  the  s})ark-plug  iiulustry.  The  highest  grade  of 
mullite  products,  trade  marked  'Durox, '  is  manufactured  by  fusing  a 
specially  concentrated  cyanite  of  great  purity  in  the  electric  furnace  at 
a  temperature  approximating  3000°  C,  whereby  a  yield  of  nearly  pure 
mullite  is  obtained. 

The  most  important  application  of  the  mullite  refractory  material  in 
its  highest  state  of  i)urity  is  in  the  form  of  glass-house  refractories,  in 
which  form  the  company's  product  is  gaining  important  recognition. 
Excellent  service  is  being  obtained  in  nmny  conunercial  installations 
on  the  Pacific  coast,  while  an  awakening  interest  in  the  east  ha^-  '^nn«pd 

'  July.   1927,  p.  58. 

-  Copy   prepared   by   the  company. 


122 


DIVISION  OF  MIXES  AND  MINING 


orders  to  be  placed  by  a  number  of  prominent  glass  manufacturers 
within  the  past  year. 

For  the  general  refractories  trade,  for  use  in  heavy-duty  boiler 
refractories  and  the  like,  a  cheaper  grade  of  mullite  is  manufactured 
and  sold  under  the  trade  mark  'California  ]\Iullite.'  This  product 
readily  competes  in  the  eastern  market  with  all  other  available  sources, 
and  has  been  pronounced  after  extensive  tests  to  be  equal  to  or  the 
superior  of  any  mullite  available  from  the  calcination  of  sillimanite. 
andalusite  or  cyanite. 

Illustrations  of  the  plant  are  shown  in  photos  Xo.  24  and  25. 

Bibl:    Curtis,    T.    S.,    Super   Kefractory   Manufacture.      Ceramic 
Industrv,  Julv.  1926. 


Photo  No.  25. 


CaUfornia  MuUite   brick  being  fired   in   tunnel  kiln  at  Cone   28, 
Vitrefrax  Co.,  Los  Angeles. 


Washingfon  Iron  Worlds.  Eighth  and  Mateo  streets,  Los  Angeles. 
This  company  ojjcrates  a  sanitary  ware  enameling  plant.  The  plant 
was  visited,  but  in  justice  to  the  company  no  details  are  published,  as 
other  manufacturers  of  this  ware  refused  publication  of  data. 

^¥estern  Brick  Co.  G.  A.  Wild,  president;  J.  J.  Lagomarsino, 
superintendent.  Office  at  Room  605,  126  AVest  Third  Street,  Los 
Angeles.  Tliis  company  manufactures  common  red  brick  only,  using 
local  clays.  Plant  No.  1  is  at  1155  Lilac  Terrace,  on  the  southern  side 
of  Elysian  Park.     The  cai)acity  of  this  plant  is  10,000,000  per  year. 

Plant  No.  2,  is  at  Twenty-sixth  and  Colorado  streets,  Santa  Monica, 
covering  the  same  clay  formation  as  th^t  occurring  on  the  property  of 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


123 


r 

it 

i 


i 


I 
I 


\ 


ar.  Either 
)ice  of  fuel 

t  and  ofifice 
I  pottery  is 
)oreelaiii  is 
1  produced. 

272),  hill 
,  from  the 
■vada  china 

from  San 

is  piped  to 
f  the  plant 
wo  Harrop 
:.  by  10-ft. 
glaze,  and 
s  the  same, 
ns  can  be 
^'mperatnre 

ant  on  the 
thers  being 
ic  plant  of 
d. 


e,  and  lies 
the  south, 

uin  Valley 

m  the  east. 

20  census). 

eons  stone, 
iron,  lead. 


section  of 
er's  Brick- 
ince  about 


64. 


Marin  County  lies  north  of  San  Francisco,  the  Marin  Peninsula  and 
San  Francisco  Peninsula  being  separated  by  the  Golden  Gate.      The 

'From  Laizure,  C.  McK.,  Marin  County:  State  Mineralogist's  Report  XXII,  p.  314, 

X926, 


122 


DIVISION  OF  MINES  AND  MINING 


orders  to  be  placed  by  a  number  of  prominent  glass  manufacturers 
within  the  past  j^ear. 

For  the  general  refractories  trade,  for  use  in  heavy-duty  boilei" 
refractories  and  the  like,  a  chea])er  grade  of  mullite  is  manufactured 
and  sold  under  the  trade  mark  '  California  Mullite. '  This  product 
readily  competes  in  the  eastern  market  with  all  other  available  sources, 
and  has  been  pronounced  after  extensive  tests  to  be  equal  to  or  the 
superior  of  any  mullite  available  from  the  calcination  of  sillimanite, 
andalusite  or  cyanite. 

Illustrations  of  the  ])lant  aro  sliown  in  j)li()tos  Xo.  24  and  25. 

Bibl :    Curtis,    T.    8.,    lSu])er   Refractory   Manufacture.      Ceramic 
Industrv,  Julv,  1926. 


Photo  No.  25. 


California  Mullite  brick  being   fired   in   tunnel  kiln  at  Cone   2S, 
Vitrefrax  Co.,  Los  Angeles. 


Washington  Iron  Worlis.  Eighth  and  ]Mateo  streets,  Los  Angeles. 
This  company  oi)erates  a  sanitary  ware  enameling  plant.  The  plant 
was  visited,  but  in  justice  to  the  company  no  details  are  published,  as 
other  manufacturers  of  this  ware  refused  publication  of  data. 

Western  Brick  Co.  G.  A.  Wild,  president;  J.  J.  Lagomarsiuo, 
superintendent.  Office  at  Room  605,  126  West  Third  Street,  Los 
Angeles.  This  company  manufactures  common  red  brick  only,  using 
local  clays.  Plant  No.  1  is  at  1155  Lilac  Terrace,  on  the  southern  side 
of  Elysian  Park.     The  capacity  of  this  plant  is  10,000,000  per  year. 

Plant  No.  2,  is  at  Twenty-sixth  and  Colorado  streets,  Santa  Monica, 
covering  the  same  clay  formation  as  th^*^  occurring  on  the  propertj^  of 


Photo  No.    24.      Interior    view   of    iilant,    Vltrefrax   Company,    Los   Angeles.      (Photo    by  courtesy  of  the  coniiiany.) 
54970 — facing  page  122 


122 


DIVISION  OF  MINES  AND  MINING 


within  the  p8 
For  the  g 
refractories  { 
and  sold  un^ 
readily  comp 
and  has  beei 
superior  of  { 
andalusite  or 
Illustratioi 

Bibl:    C 
Indiisl 


Photo  No.   2! 


Washingto 
This  compan 
was  visited,  1 
other  manuf  £ 

Western  1 
superintende 

Angeles.     Th  ^      ^  .  .  _ 

local  clays.    Plant  No.  1  is  at  1155  Lilac  Terrace,  on  the  southern  side 
of  Elvsian  Park.     The  capacity  of  this  plant  is  10,000,000  per  year. 

Plant  No.  2,  is  at  Twenty-sixth  and  Colorado  streets,  Santa  Monica, 
covering  the  same  clay  formation  as  th^t  occurring  on  the  property  of 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  123 

the  Los  Aiipfeles  Pressed  Brick  Company  and  tlie  Simons  Brielc  Com- 
pany. This  plant  has  a  capacity  of  25,000,000  brick  jjer  year.  p]ither 
oil  or  <?as  fuel  is  used  for  firing  in  open  field  kilns,  the  choice  of  fuel 
depending  upon  relative  economy  at  the  time. 

Whiting-Mead  Company.  J.  M.  Bonner,  secretary.  Plant  and  office 
at  2260  E.  Vernon  Street,  Los  Angeles.  The  Whiting-Mead  pottery  is 
one  of  the  largest  on  the  Pacific  coast  in  which  sanitary  porcelain  is 
manufactured.  A  small  quantity  of  garden  i)ottery  is  also  produced. 
The  clays  used  are  a  white  clay  from  Corona  (No.  70,  p.  272),  hill 
blue  (No.  9,  ]).  287),  and  ])ink  mollled  (No.  7,  ]).  328),  from  the 
Alberhill  Coal  and  Clay  Co.,  Englisli  cliina  and  ball  clays,  Nevada  china 
clay  from  near  Cuprite,  in  addition  to  silica  and  feldspar  from  San 
Dieeo  County. 

Tlie  casting  procecss  is  used  exclusively.  The  clay  sli])  is  piped  to 
all  ])arts  of  the  casting  room,  which  is  on  the  second  floor  of  the  plant 
building.  Waste-heat  driers  are  used.  The  ware  is  fired  in  two  Harrop 
tunnel  kilns,  each  365  feet  long,  using  trucks  5-ft.  by  5-ft.  by  10-ft. 
After  the  biscuit  firing  in  the  first  kiln,  the  ware  is  dipped  in  glaze,  and 
is  glost  in  the  second  kiln.  The  firing  cycle  in  the  two  kilns  is  the  same, 
66  hours,  so  that  the  loading  and  unloading  of  the  kilns  can  be 
synchronized.  Precious  metal  thermocouples  are  used  for  temperature 
control  in  the  kilns. 

The  company  also  operates  a  .sanitary  ware  enameling  plant  on  the 
same  site.  It  is  one  of  three  such  plants  in  California,  the  others  being 
the  Washington  Iron  Works  of  Los  Angeles  and  the  Pacific  plant  of 
the  Standard  Sanitary  Manufacturing  Company  at  Richmond. 

MADERA   COUNTY. 
General    Features. 

Madera  County  is  in  the  east-central  portion  of  the  state,  and  lies 
between  IMerced  and  Mariposa  on  the  north  and  Fresno  on  the  south, 
in  a  narrow  strip,  extending  from  the  floor  of  the  San  Joaquin  Valley 
on  the  west  to  tlie  sunnnit  of  the  Sierra  Nevada  iMountains  on  the  east. 
Its  area  is  2112  square  miles,  and  the  population  is  12,203  (1920  census). 
Granite  is  the  principal  mineral  product.  Some  miscellaneous  stone, 
gold  and  silver  are  also  produced.  Occurrences  of  copper,  iron,  lead, 
molybdenum,  pumice,  and  building  stone  are  known. 

Clay    Resources. 

Common  brick  clay  is  reasonably  abundant  in  the  valley  section  of 
the  county.  The  Sunset  Brick  Company  (also  known  as  Dyer's  Brick- 
vard)  operated  at  ]\Iadera  for  a  time,  but  has  been  idle  since  about 
1919. 

Bibl :  State  Min.  Bur.  Bull.  38,  p.  249 ;  Prel.  Kept.  7,  p.  64. 

MARIN    COUNTY. 
General    Features.' 

Marin  County  lies  north  of  San  Francisco,  the  Marin  Peninsula  and 
San  Francisco  Peninsula  being  separated  by  the  Golden  Gate.      The 

iFrom  Laizure,  C.  McK.,  Marin  County:  State  Mineralogist's  Report  XXII,  p.  314, 
192(5. 


124  DIVISION  OF  MIXES  AND  MINING 

Pacific  Ocean  bounds  it  on  the  west,  Sonoma  County  and  portions  of 
San  Pablo  and  San  Francisco  bays  surround  it  on  the  north  and  east. 
The  total  area  of  the  countv  is  529  square  miles,  and  the  ])oinilation  is 
27,3-42  (1920  census). 

The  main  line  of  the  Northwestern  Pacific  railroad  runs  throu^rh  the 
eastern  side  of  the  county,  and  a  narrow-<iauge  branch  traverses  the 
western  portion,  passing  through  Point  Reyes  and  continuing  north- 
ward into  Sonoma  County. 

Marin  County  is  for  the  most  part  rugged  and  picturesque,  the 
ridges  having  steep  sloi)es  with  only  a  few  small  flat  valleys.  The  main 
ridge  trends  northwesterly,  culminating  at  the  south  in  Mount  Tamal- 
pais,  which  overlooks  both  bay  and  ocean  from  an  elevation  of  2601  feet. 
From  this  main  crest  the  drainage  is  both  to  the  ocean  and  bay  sides. 
Other  notable  topographic  features  are  Tomales.  Drakes,  Bodega  and 
Bolinas  bays  on  the  ocean  side  and  Richardsons  Bay  on  the  inland  side. 

Geology. 

The  geology  of  the  ]\Iarin  Peninsula  has  been  described  by  Lawson  ^ 
and  Osmont,"  to  which  the  reader  is  referred  for  a  detailed  discussion. 

Geologically,  the  county  is  divided  into  two  areas  by  the  great  San 
Andreas  fault,  which  runs  in  a  northwest  direction  from  Bolinas  Bay 
to  Tomales  Bay.  The  country  lying  east  of  the  fault  comprises  about 
three-fourths  of  the  county  and  is  compo.sed  almost  entirely  of  Fran- 
ciscan rocks.  These  include  massive  sandstone,  chert  and  intrusive 
bodies  of  serpentine  and  basalt.  The  Point  Reyes  Peninsula,  which 
includes  that  portion  of  the  county  lying  west  of  San  Andreas  fault,  is 
composed  mainly  of  Monterey  shale,  which  is  distinctly  bituminous  in 
places.  Two  small  areas  of  volcanic  rock  are  exposed  near  Inverness 
and  Tomales  Point. 

The  mineralization  of  the  county  is  diversified,  but  the  deposits  that 
may  be  classed  as  economic  resources  are  limited,  though  important 
on  account  of  their  proximity  to  the  metropolitan  bay  area.  The  eco- 
nomic minerals  are  mainly  structural  and  industrial  nonmetallic  prod- 
ucts. Occurrences  have  also  been  noted  of  asi)haltum,  petroleum,  chro- 
mite,  coal,  jasper,  garnets,  manganese,  mineral  water,  and  natural  gas. 
A  little  copper  ore  was  at  one  time  shipped,  and  traces  of  gold  and 
silver  have  been  found.     Salt  has  been  produced. 

Clay    Resources. 

No  deposits  of  high-grade  clay  have  been  reported  in  the  county,  but 
there  is  an  adequate  supply  of  clay  and  shale  suitable  for  the  manufac- 
ture of  red  structural  ware  at  numerous  places  in  the  county.  Common 
brick  and  other  products  have  been  produced  since  1870  and  three 
plants  have  been  in  operation  at  various  times  in  the  past.  One  plant 
is  at  present  steadily  producing,  and  a  second  plant  is  under  construc- 
tion. 

McNear  Brick  Co.  E.  B.  McNear,  |)resident  and  manager;  L.  B. 
McNear,  superintendent.  ^Main  office,  417  Berry  Street.  San  Francisco. 
Manufacturers  of  connnon  brick. 

The  clay  ])it  and  brick  yard  are  at  tidewater  on  ^McNear  Point,  four 
miles  east  of  San  Rafael.     The  present  i)it  is  3000  feet  from  the  plant, 

'  Lawson,   A.   C,   San    Fi-ancisco  FoHo,  No.   19:;,  U.   S.  Geol.    Survev. 
=  Osmont,  V.  C,  Bull.  Dept.  of  Geology,  Univ.  of  Calif.,  Vol.  4,  No.  3. 


CLAY  RESOURCES  AXD  CERAMIC  IXDUSTRY 


125 


in  a  bank  of  sliale,  slate,  sandstone  and  clay  in  the  face  of  a  hill,  under- 
lain by  Franeiscan  sandstone.  The  material  sometimes  re(|uires  l)lastin<i\ 
It  is  deliveretl  to  a  luadinji'  hopper  by  two  electi-ically  operatetl  tlraj;'- 
line  scrapers  operatino:  on  a  lO/c  slope  in  favor  of  the  load.  The  clay 
bank  has  the  form  of  an  arc  of  a  circle,  with  a  radius  of  300  yards,  and 
a  center  at  the  loadinjr  hoi)per.  The  unblasted  bank  stands  at  a  heijjht 
of  'M)  to  (jO  feet,  and  has  a  nearly  vertical  face.  A  view  of  the  pit  is 
shown  on  i)hoto  No.  26. 

From  the  loading;  hopper,  the  clay  is  loaded  by  a  chain  conveyor  into 
2.")  cu.  yd.  side-dump  eonti'actoi-'s  ears.  Ti'ains  of  four  ears  each  are 
hauled  to  the  plant  by  a  Jialdwin  Westinghouse  electric  trolley  loco- 
motive. 

At  the  plant,  the  clay  is  fed  to  two  9-ft.,  dry-])ans,  elevated  by  a 
bucket  elevator  and  delivered  to  a  pu<>'  mill  and  auger  machine,  e(iui])ped 
with  a  wire  cutter.  Drying  is  done  under  sheds,  and  reiiuires  15  days 
(average)  in  summer,  and  a  longer  time  in  winter.     Firing  is  done  in 


Photo  No.  26.  Clay  and  shale  deposit  of  McNear  Brick  Company,  showing 
loading  hopper.  Marin  County.  (From  State  Mineralogist's  Report  XXll, 
p.  318,   1927.) 

two  Hoffman  continuous  kilns,  fired  with  coal  screenings  or  oil  coke. 
The  kiln  turnover  i)eriod  is  15  days,  and  actual  firing  requires  from  five 
to  .six  days.     The  finishing  temi)erature  is  2000°  F. 

The  capacity  of  the  plant  is  60,000  common  brick  i)er  day.  From  45 
to  50  men  are  employed. 

Sample  No.  198  was  taken  from  the  dry-pan  feed.  The  superintend- 
ent stated  that  the  sample  was  somewhat  leaner  than  the  normal  feed 
to  the  plant  as  it  had  rained  the  previous  night,  and  only  the  more 
sandy  clay  can  be  handled  wlien  the  ground  is  wet.  The  test  results 
are  on  page  329.  Occasional  seams  containing  calcite  are  encountered 
in  the  pit.  These  can  be  included  in  the  mix  if  they  are  well  distributed 
in  the  feed  to  the  plant. 

Bibl :  State  Mineralogist's  Reports  VIII,  p.  342 ;  XII,  p.  382 ;  XIII, 
p.  615 ;  XIV,  p.  244 ;  XXII,  p.  317.  Bull.  No.  38,  p.  249.  Prel. 
Kept.  No.  7,  p.  64. 


126  DIVISION  OF  MINES  AND  MINING 

Louis  Sharhori^  554  Broadway,  San  Francisco,  has  recently  (1926) 
leased  tlie  Keiiiillard  j)i'opei-ty    (see  posi)   and   was  exi)ected  to  begin 
the   manufacture   of   floor    tile    dui-inu    1927.       No    further   data    are 
available. 

Earlier  Kkports. 

The  status  of  operations  or  clay  deposits  noted  in  previous  reports- 
is  as  follows : 

Maillard  Ranch.  Lagunitas.  Now  owned  by  the  Lagunitas  Develop- 
ment Company,  833  Market  Street,  San  Francisco.  "Clay  deposit  on 
Spring  Creek,  about  eight  miles  nortliAvest  of  San  Kafael."  Tlie  deposit 
is  still  undeveloped,  and  is  ])robably  common  clay. 

Patent  Brick  Companij.  Galliiias  Station.  This  ])lant  has  been  dis- 
mantled, and  the  company  is  out  of  business.  The  liidecker  Tile  Co., 
Twenty-fourth  and  Union  streets,  Oakland  (see  under  Alameda 
County),  occasionally  crushes  some  of  the  old  brick  from  this  place  for 
use  in  the  manufacture  of  roofing  tile. 

RemiUard  Brick  (U)mpanij.  Greenbrae.  "Shale  and  sandstone,  ])rac- 
tically  inexhaustible."  Tliis  plant  was  dismantled  about  1911.  The 
company  operates  plants  at  Pleasanton,  Alameda  County,  and  at  San 
Jose,  Santa  Clara  County  (9  v.). 

Bibl  (On  ]\Iarin  Countv  clav  resources)  :  State  ^Mineralogist 's 
Reports  V,  p.  lOS ;  VllI,  p.  342;  XI,  p.  253;  XII,  pp.  329.  382; 
XIII,  pp.  506,  615;  XIV,  pp.  24-1-248;  XX 11.  ])p.  317-319.  Bull. 
38,  p.  362 ;  Prel.  Kept.  7,  p.  64. 

MENDOCINO   COUNTY. 
General   Features. 

Mendocino  County  joins  Humboldt  County  on  the  south  and  is 
bounded  by  the  Pacific  Ocean  on  the  west.  Its  area  is  3453  square 
miles,  and  the  population  is  24,116  (1920  census).  Lying  in  the  Coast 
Range,  the  greater  part  of  the  county  is  mountainous  and  heavily  tim- 
bered, except  in  the  southeastern  portion,  through  which  flows  the 
Russian  River.     Lumbering  is  an  important  industry. 

The  rocks  of  the  Coast  Range  within  the  limits  of  the  county  consist 
mainly  of  Franciscan  (Jurassic),  Chico  (Upper  Cretaceous),  and 
various  Tertiary  sedimentary  and  metamorphic  formations.  The  min- 
eral resources  are  largely  undeveloped.  Occurrences  of  asbestos, 
chromite,  coal,  copper,  graphite,  magnesite,  and  mineral  water  are 
known,  as  well  as  traces  of  gold,  platinum,  and  silver.  j\Iiscellaneous 
stone,  coal  and  natural  gas  are  produced  in  small  amounts. 

Clay   Resources. 

Common  brick  clays  are  available  near  the  coast  at  the  town  of 
]\Iendocino,  and  also  at  Ukiah.  Brickyards  were  at  one  time  operated 
in  these  places,  and  at  Talmage,  near  LHviah,  but  there  has  been  no  pro- 
duction in  recent  years.  The  brickyard  of  U.  N.  Briggs,  at  Ukiah,  has 
been  out  of  business  since  1922.  The  most  recent  production  of  com- 
mon brick  was  at  the  Mendocino  State  Hospital,  at  Talmage.    See  below. 


'  Laizure,   op.   cif.,  p.    ?.19. 

=  Especially  in  Prel.  Rept.   7,  p.  64. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  127 

Mendocino  State  Hospital.  Talmaj^^e.'  A  brickyard  was  operated 
here  for  a  few  yeai's  to  iiiajuifai'turc  l)riek  for  use  in  eonstruetion  work 
at  the  liospital.  The  elay  eousisted  ol'  a  hx-al  (lei)osit  of  gravelly  silt, 
about  10  feet  deep,  and  covering  an  ai'ea  of  al)out  one-half  acre.  It 
was  mined  with  a  ])low  and  sci-aper.  The  plant  is  eciuipped  with  a 
disintegrator,  conveyor,  pug-mill,  and  auger  machine,  with  a  wire 
cutter.  The  lack  of  screening  equipment  reduced  the  capacity  of  the 
machinery  to  8000  brick  per  day  instead  of  30,000,  on  account  of  gravel 
in  the  clay.  Firing  was  done  in  open  field  kilns.  The  ])roduction  cost 
of  the  brick  was  stated  to  be  $11.50  per  thousand.  There  has  been  no 
production  since  1924,  as  it  was  found  tiuit  concrete  construction  is 
cheaper,  with  cement  at  $2.28  per  barrel,  delivered. 

l'>ibl:   State  Mineralogist's  Kept.   XIV.   p.   415;   State  Min.   Bur. 
Prel.  Kept.  7.  p.  04. 

MERCED   COUNTY. 
General  Features." 

^Merced  County  is  situatetl  lU'ar  the  geographical  center  of  the  state. 
It  is  bounded  on  the  north  by  Stanislaus  County,  on  the  east  by  ]\Iari- 
posa,  on  the  south  by  Madera  and  Fresno,  on  the  west  by  Santa  Clara 
and  San  Benito  counties.  It  has  an  area  of  1995  scjuare  miles  and  sup- 
ports a  population  of  24,579  (1!)20  census),  ^lost  of  the  land  is  culti- 
vated, and  much  of  it  is  irrigated,  there  being  extensive  irrigation 
systems  covering  the  valh'y  lands.  ]\Ierced  is  essentially  an  agricultural 
county. 

The  greater  part  of  the  county  lies  within  the  San  Joacjuin  Valley, 
and  is  comi)osed  of  unconsolidated  sands,  gravels,  and  clays  of 
(^uateinary  age.  Along  the  eastern  edge  of  the  county  there  is  a  narrow 
belt  of  Tertiary  formations,  represented  mainly  by  clays,  shale  and 
massive  sandstone.  On  the  western  side  of  the  county  ('retaceous  sand- 
stones and  shales  appear,  and  as  the  western  boundary  of  the  county, 
near  the  summit  of  the  Coast  Kange,  is  ap])roache(l,  Franciscan  rocks  of 
•Jurassic  age  are  exclusively  in  evidence.  These  consist  mainly  of 
slates,  cherts,  sandstones,  schists,  and  serpentine. 

Both  metallic  and  nonmetallic  minerals  have  been  found  and  pro- 
duced in  Merced  County.  Among  the  former  are  gold,  platinum,  silver, 
cop])er,  and  a  few  ])ounds  of  lead.  Crushed  rock,  gravel,  sand,  clay, 
and  clay  products  are  the  chief  nonmetallics.  In  addition  to  these  the 
occurrence  of  a  few  other  minerals  has  been  noted,  such  as  cinnabar 
(quicksilver),  stibnite  (antimony),  barite,  calcite,  diatomaceous  earth, 
magnesite,  asbestos,  manganese,  coal,  and  soda  niter,  but  for  the  most 
part  these  are  entirely  undeveloped  and  probably  most  of  them  do  not 
occur  in  marketable  quantities. 

Miscellaneous  stone,  including  crushed  rock,  gravel,  and  sand,  cement, 
brick  and  tile,  are  at  the  present  time  the  principal  mineral  products. 
Structural  materials  of  this  nature  will  contribute  almost  exclusively 
to  the  future  mineral  output  of  the  county. 

Clay    Resources. 

No  commercial  deposits  of  high-grade  clay  have  been  found  in  the 
county,   notwithstanding   intensive   investigations   on  the   part   of  the 

'  Information  secured  through  the  courtesy  of  Dr.  Donald  R.   Smith. 
2  From    Laizure,    C.    Mc-K..    Merced    County:    State    Mineralogist's    Report   XXI.    p. 
173,   et  seq.,  1925. 


128  DIVISION  OP  MINES  AND  MINING 

I'alifornia  Pottery  romi)any  and  the  Yosemite  Portland  Cement  Com- 
pany. The  hitter  company  recently  built  a  cement  plant  near  ]\Ierced 
and  conducted  an  elaborate  search  for  high-alumina  clay,  low  in  iron, 
but  were  finally  forced  to  import  this  material  from  the  lone  district. 

There  are  a  few  remnants  of  the  lone  formation  in  the  foothills  of 
Merced  County.  These  have  not  been  thoroughly  prospected,  but  there 
seems  little  reason  to  hope  for  commercial  clay  dejiosits  in  them. 

Clay  suitable  for  the  manufacture  of  common  brick  and  hollow  tile 
is  available  in  the  vicinity  of  Merced.  A  brickyard  operated  in  Pierced 
from  1905  to  1910.  The  clays  from  various  i)laces  are  now  being  used 
by  the  California  Pottery  Company  (see  post),  the  Yosemite  Portland 
Cement  Company,  and  the  Craj'croft-Herold  Brick  Company  of  Fresno. 
The  latter  company  mines  clay  from  a  deposit  six  miles  south  of  Merced, 
and  shii)s  to  its  jilant  in  Fresno. 

California  Pottery  Co.  F.  A.  Co.stello,  president.  General  of^ce. 
Mills  Building,  San  Francisco.  Plant  at  Merced.  The  company  also 
operates  a  plant  in  Oakland,  Alameda  County.  The  Merced  plant  is  in 
the  southern  outskirts  of  Pierced,  between  the  state  highway  and  the 
Southern  Pacific  railroad.  The  ])roducts  of  the  plant  are  roofing  tile, 
hollow  tile,  and  some  3-in.  to  6-in.  drain  tile.  Red,  buif,  and  pink 
ruffled  face  brick  were  formerly  made. 

The  local  clav  is  mixed  with  clav  from  the  company's  pit  near  Valley 
Springs,  Calaveras  County  (samples  Xo.  202-204.  pp.' 299  and  337),  and 
with  red-burning  clay  from  the  Xatoma  Clay  Company  in  Sacramento 
C^ounty  (.samples  No.  210  and  212,  p.  337).  The  local  clay  is  a 
valley  silt,  and  is  mined  to  a  depth  of  10  feet  with  team  and  scrajier 
from  a  ])it  adjoining  the  plant.  It  has  in.sufficient  bonding  strength 
and  plasticity  to  be  used  alone,  and  at  least  359c  of  the  Valley  Si)rings 
clay,  or  an  e(|uivalent  amount  of  Natoma  clay  mu.st  be  mixed  with  it. 

The  plant  is  equipped  with  a  10-ft.  Raymond  dry  pan,  one  American 
number  290  auger  machine  for  hollow  tile  and  face  brick,  one  American 
No.  233  auger  for  roofing  tile,  a  20-tunnel  American  waste-heat  drier, 
and  eight  30-ft.,  oil-fired,  steam-atomized,  round  down-draft  kilns. 
The  dryer  cycle  is  36  hours.  When  there  is  insufficient  dryer  capacity, 
.some  ware  is  dried  on  the  drier  floor.  Each  of  the  kilns  has  a  capacity 
of  125  tons  of  hollow  tile.  100  tons  of  Sierra  roofing  tile,  or  90  tons  of 
Spanish  roofing  tile.  Firing  requires  72  hours,  to  a  maximum  tempera- 
ture of  cone  4—5  (1170°  C.)  for  buff -colored  ware,  and  to  cone  2 
(1135°  C.)  for  red-colored  ware.  Seventy-five  per  cent  of  the  output 
of  the  plant  during  1925  was  roofing  tile.  The  output  of  drain  tile 
is  very  .small. 

The  plant  is  handicapped  by  the  fact  that  clay  must  be  brought  in 
from  the  north,  and  at  the  same  time,  the  principal  market  for  the 
])roducts  are  to  the  north. 

Forty -three  men  are  emploj'ed. 

M.  Goldman^  of  Merced  is  the  owner  of  large  land  holdings  in  the 
eastern  ])art  of  the  county,  and  it  has  been  reported  in  the  past  that 
white  clay,  .suitable  for  the  manufacture  of  pottery,  occurs  on  this  prop- 
erty in  the  vicinity  of  Merced  Falls.  The  holdings  have  not  been  thor- 
oughly prospected,  but  the  investigations  that  were  made  failed  in  find- 

^  Laizure,  C.  McK.,  op.  cit.,  p.   179. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  1  29 

iii^'  any  liij^li-^'j'adc  clay;  llic  malciial  hriiii;-  apparently  a  silt  (h^jMtsit 
of  iiKJcfinito  coiiiposil  ion,  i-atli<M-  tliaii  a  icsidual  cla.w 

Clay  (l('i)(>sits  liav(>  bocii  i-t']»()i-1('(l  from  'W  o  S.,  11.  14  10.  'riicir  char- 
acter and  value  have  not  been  determined. 

J5ibl  (Merced  Countv  clav  resources)  :  State  iMineralogist's 
Keports,  XIV,  p.  605;  XXl,  pp.  175,  177-179.  Bull.  38,  pp.  217, 
250;  Prel.  Kept.  7,  p.  64. 

MONTEREY  COUNTY. 
General    Features.' 

Montere.y  is  one  of  the  central  coast  counties,  extending  from  the 
Pajaro  River,  MJiicli  emi)ties  into  Monterey  Bay,  south  to  the  sixth 
Standard  ParaUel.  It  i.s  bounded  on  the  north  by  Santa  Cruz  County. 
San  Benito,  Fresno  and  Kings  counties  adjoin  it  on  the  east,  and  San 
Luis  Obispo  County  bounds  it  on  the  south.  Its  area  is  3330  square 
miles  and  its  population  27,980  (1920  census).  The  main  line  of  the 
Southern  Pacific  railroad,  coast  division,  runs  through  the  count}^  con- 
necting it  with  San  Francisco  and  Los  Angeles,  as  also  does  the  state 
highway,  a  concrete  paved  road.  Connecting  county  roads  are  kept  in 
good  condition,  and  it  is  only  in  the  more  remote  mountainous  sections 
that  economic  transportation  becomes  a  problem.  Tlie  completion  of 
the  ])roposed  road  along  the  coast,  connecting  Monterey  and  San  Luis 
Obispo,  now  open  from  the  north  to  a  point  18  miles  beyond  Big  Sur 
and  from  the  southern  end  as  far  norlli  as  Salmon  Creek,  will  open  up  a 
lai'ge  area  which  has  heretofore  been  accessible  only  by  water  or  steep 
trails,  and  one  whose  mineral  resoui'ces  are  scarcely  known. 

Among  the  principal  topographic  features  is  the  great  central  Salinas 
Valley,  the  largest  of  the  intermountain  valleys  of  the  coast  region, 
being  about  100  miles  long  by  6  to  10  miles  in  width,  and  lying  parallel 
to  th(>  coast.  P>etween  the  valley  and  the  coast  rises  the  Santa  Lucia 
]Mou)itain  Range,  which  culminates  in  a  number  of  peaks,  some  reacliing 
nearly  6000  feet  above  sea  level.  Along  the  eastern  side  of  the  valley, 
and  with  their  crests  forming  the  eastern  boundary  of  the  county,  are 
the  Gavilan  and  Diablo  ranges.  Among  the  smaller  valleys  are  the 
San  Lorenzo,  San  Antojiio,  Cholame,  Carmel,  and  Nacimiento.  In  each 
of  these  the  ])rincipal  axis  extends  noi'tli westerly,  parallel  witli  the 
general  structure  of  the  mountain  ranges. 

Geology. 

The  geology  of  most  of  Monterey  County  is  described  and  ma])ped  in 
Bulletin  No.  69  of  the  State  Mining  Bureau,  'Petroleum  Resources  of 
California,'  and  the  folio  accompanying  it.  It  is  also  shown  in  lesser 
detail  on  the  Geological  Maj)  of  California  (1916). 

The  Santa  Lucia  Range  has  a  core  of  granitic  rock.  This  is  exposed 
in  Santa  Lucia  Peak  at  an  elevation  of  5967  feet,  and  throughout  the 
territory  between  Carmel  River  and  Sur  River,  either  along  the  coast 
or  in  the  river  cuts.  Limestone  and  gneiss  overlie  the  granite  in  places, 
and  make  up  Pico  Blanco,  Ventana  Cone,  Marble  Peak,  Twin  Peak,  and 
Cone  Peak.  Most  of  the  area  from  Mill  Creek  southward  to  Three  Peaks 
and  bounded  on  the  northeast  bj"  Nacimiento  River  is  made  up  of  Fran- 

»  Laizure,  C.  McK.,  Monterey  County:   State  Mineralogist's  Report  XXI,  p.  23,  1925. 
9 — 54979 


130  DIVISION  OP  MINES  AND  MINING 

ciscau  sandstone  and  shale,  witli  intrusions  of  serpentine.  It  is  in 
the  region  of  these  serpentine  intrusions  and  the  later  intrusive 
acid  dikes  that  tlie  important  mineral  deposits  of  the  Los  l>urros 
district  are  found.  The  geology  of  tlie  Los  Burros  district  has  been 
described  in  considerable  detail  by  Ilill.^  There  is  evidence  throughout 
of  much  faulting,  and  the  precipitous  coast  follows  a  fault  line.  Monte- 
rey sandstone  and  conglomerate  flank  the  mountains  on  the  soutliwest 
side  of  Nacimiento  River,  and  dip  towards  the  valley.  Most  of  the 
older  sediments  exposed  east  of  the  Nacimiento  consist  of  Monterey 
shale,  which  is  considerably  folded  east  of  Jolon. 

Along  the  coast,  resting  unconformabl}^  on  the  granite  and  Franciscan 
rocks,  are  raised  beach  deposits.  The  settlement  of  Gorda  is  located 
on  the  most  recent  of  these  terraces.  This  terrace  is  noticeable  in 
Willow  Creek,  one-half  mile  back  from  its  mouth,  and  also  along  the 
coast  north  of  Gorda.  These  terraces  are  important  in  relation  to  placer 
gold.  It  is  thought  that  the  placer  deposits  near  Jolon  originated  in  a 
similar  manner. 

In  the  northeastern  part  of  the  county,  in  the  Gavilan  Range,  granite 
occurs  associated  with  gneisses  and  schists.  In  places  these  rocks  con- 
tact with  massive  beds  of  metamorphosed  limestone,  and  dolomite  is 
commonly  associated  with  them.  Feldspathic  segregations  give  rise  to 
commercial  deposits  of  feldspar  along  the  range  as  far  south  as  the 
Pinnacles.  In  the  vicinity  of  the  Pinnacles  there  is  a  small  area  wdiere 
volcanic  activity  has  taken  place  and  extrusive  volcanic  rocks  are  in 
evidence.  Farther  south  Tertiary  sandstone  and  shales  predominate. 
A  long,  narrow  belt  of  the  Franciscan  rocks,  including  slates,  sand- 
stones, and  much  schist  and  serpentine,  extends  from  Priests  Valley 
southeastward  beyond  Parkfield.  AVorkable  coal  beds  are  exposed  in 
the  vicinity  of  Priests  Valley  and  the  principal  quicksilver  deposits 
occur  in  the  Franciscan,  not  far  from  Parkfield. 

The  following  commercial  minerals  are  of  record  as  occurring  in 
Monterey  County:  Arsenopyrite,  barite,  bitumen  (asphaltnm),  calcite 
(limestone  and  marble),  ehromite,  cinnabar  (quicksilver),  clay,  coal, 
copper,  diatomaceous  earth,  dolomite,  galena,  garnet,  gold,  graphite, 
gypsum,  magnesite,  magnetite,  malachite,  metacinnabarite,  molybdenite, 
orthoclase  (feldspar),  psilomelane  (manganese),  quartz,  salt,  serpen- 
tine (asbestos),  and  stibnite.  Not  all  of  these  have  been  produced  in 
commercial  quantities,  however,  nor  is  it  known  that  all  occur  in  suf^- 
cient  quantity  to  be  of  value.  About  ten  other  species  of  miiieralogical 
interest  only  have  also  been  noted. 

Clay   Resources. 

No  commercial  deposits  of  high-grade  clays  have  been  discovered  in 
the  county.  Common  brick  clays  are  not  abundant,  but  there  is  little 
doubt  that  suitable  deposits  can  be  found  if  needed  for  local  purposes. 
A  clay  pit  and  brickyard  were  at  one  time  operated  on  a  small  scale  at 
the  south  end  of  Salinas.  The  only  clay-working  operations  in  the 
county  at  present  (1927)  are  two  hand-made  roofing  tile  plants,  which 
are  described  below. 

Area  Hoofing  Tile  Plant.  Joe  Area  of  Castroville  owns  and  operates 
a  small  hand-made  roofing-tile  plant  one  mile  east  of  Castroville  on  the 

1  Hill,  J.  M..  The  Los  Burros  District,  Monterey  County,  California  :  U.  S.  Geol. 
Survey  Bull.  No.  735-J,  1923. 


CLAY  RESOURCES  AND  CERAI^tlC;  INDUSTRY  lol 

Salinas  road.  The  property  covers  one  acre.  The  clay  deposit  consists 
of  18  ft.  of  yellow  plastic  clay,  underlying  one  foot  or  less  of  black 
adobe.  See  sample  No.  117,  ])age  ;i24,  for  test  data  on  the  clay.  Tlie  clay 
is  mined  ])y  hand  and  is  fed  to  a  horse-driven  ]ing-mill.  After  the 
l)uyged  clay  is  aged  for  a  few  days,  the  tile  arc  shaped  by  hand  over 
wooden  forms,  and  are  then  dried  in  air  under  sheds.  The  clay  is 
excessively  plastic,  and  in  the  cool  moist  climate  of  the  region,  drying 
is  very  slow.  The  tile  are  fired  in  an  oil-fired  rectangular  u])-draft  kiln. 
The  capacity  of  the  plant  is  500  tile  per  day,  and  three  or  four  men 
are  employed. 

Mr.  Area  reports  that  good  roofing  tile  clay  occurs  on  the  Martin 
ranch  near  the  Carmel  mission.  It  was  u.sed  by  the  Indians  in  making 
roofing  tile  for  the  IMission.  ]\Ir.  Area  attempted  to  establish  his  plant 
there  but  found  that  the  land  was  too  valuable. 

Monterey  Mission  Tile  Co.  II.  L.  Watson,  i)resident;  T.  II.  Bane, 
secretary  treasurer.  The  new  plant  of  the  jMonterc}-  ]\Iission  Tile  Com- 
pany is  near  Seaside,  and  about  two  miles  north  of  Del  Monte.  The 
property  covers  thi-ee  acres.  The  products  are  red-burned  roof  tile, 
floor  tile,  and  step  tile,  all  of  which  are  hand-made.  The  clay  is  mined 
by  hand  methods  from  the  Thomas  Field  ranch  on  the  Laguna  Seco 
grant,  at  a  point  5.5  miles  toward  Salinas  from  the  junction  of  the 
Salinas  road  and  the  Santa  Cruz  road  just  north  of  Del  IMonte.  The 
total  haul  to  the  plant  is  seven  miles.  The  clay  is  a  black  adobe,  10 
feet  deep,  covered  with  2  feet  of  sandy  soil.  Sample  No.  214  was  taken 
from  the  clay  in  storage  at  the  plant.     See  page  327. 

At  the  plant,  the  clay  is  mixed  with  approximately  20%  of  grog  con- 
sisting of  ground  rejects  from  the  kiln,  pugged  in  a  Patterson  vertical 
pug-mill,  and  aged  for  at  least  three  days  before  molding.  A  5-hp. 
motor  drives  the  grog  crusher  and  the  pug  mill. 

The  tile  are  shaped  by  hand  with  Mexican  labor,  and  are  dried  under 
sheds.  The  drying  time  varies  widely  Avith  climatic  conditions,  but 
usually  requires  at  least  two  Aveeks,  on  account  of  the  cool,  humid 
atmosphere  generall.v  prevailing  in  this  region. 

The  tile  are  fired  in  a  cylindrical  up-draft  kiln,  13^  feet  in  diameter 
in  the  lower  6-ft.  section,  tapering  to  six  feet  in  diameter  in  the  upper 
5-ft.  section,  and  finally  tapering  to  four  feet  in  diameter  at  the  throat. 
The  kiln  will  hold  ai)iU'oxinuitely  (iOO  roofing  tile.  Tt  is  fired  with  four 
oil  burners,  placed  in  pairs  at  opposite  sides  of  the  kiln.  The  oil  is 
preheated  to  120°  F.  in  electric  heaters  placed  in  the  pipe  line,  and  is 
atomized  with  air  from  motor-driven  blowers.  Four  base-metal  thermo- 
couplos.  with  a  multiple  rccordci-,  are  used  to  control  the  firing,  in  addi- 
tion to  Orton  standard  cones.  The  niaxinnnn  temperatures  recorded  at 
the  end  of  firing  are  1830°  F.  on  the  bottom,  and  1470°  F.  on  the  top 
of  the  kiln.     Firing  requires  32  to  38  hours. 

The  product  is  distinctly  different  in  appearance  from  machine-made 
tile,  and  from  most  of  the  hand-made  tile  produced  in  the  state,  on 
account  of  the  irregular  texture  and  the  play  of  colors  to  be  seen  on 
each  individual  tile.  The  owners  of  the  plant  were  formerly  builders 
in  the  district,  and  the  tile  plant  is  the  outgrowth  of  a  local  desire  for 
more  artistic  effects  than  could  be  obtained  with  the  tile  previously  on 
the  market.     Since  the  tile  are  made  by  an  expensive  process,  they  are 


132  DIVISION  OF  MINES  AND  MINING 

only  to  be  seen  on  some  of  the  finest  residences  in  Carmel  and  Pebble 
Beach. 

From  8  to  10  men  are  emploj'cd  when  the  plant  is  in  fnll  operation. 

Bibl:  State  Mineralogist's  Report  XXI,  p.  57,  Jan.  1925. 

Miscellaneous  Deposits. 

Echstine  Deposit.  Mrs.  G.  P.  Echstine,  Pleyto.  In  T.  24  S.,  R.  8  E., 
M.  D.  M.  An  ocenrrence  of  white  plastic  clay  had  been  reported  to  the 
Burean.  The  deposit  was  investigated  in  September,  1926,  and  was 
found  to  consist  of  a  plastic  clay  that  is  graj'ish  white  when  dry,  but 
darkens  considerably  when  wet,  and  fires  to  a  red  color.  The  property 
is  difficult  of  access,  and  is  some  18  miles  from  the  railroad,  hence  the 
clay  has  no  possible  commercial  value. 

Heins  Lal-e  Deposit.  Owner,  Martha  E.  Bardin,  Salinas.  Tlie  bot- 
tom of  Heins  Lake,  now  dry,  situated  about  two  miles  southeast  of 
Salinas,  is  reported  to  be  composed  of  blue  clay.  There  is  about  300 
acres  in  the  deposit,  and  it  is  said  to  average  four  feet  in  depth. ^  No 
investigation  was  made  by  the  author. 

Jens  Deposit.  Chualar.  A  supposed  deposit  of  clay  from  wliieli  it 
was  reported  that  several  thousand  tons  had  been  shii)pe(l.  An  investi- 
gation showed  that  the  material  is  low-grade  feldspar. 

Bibl  (Clav  resources  of  Monterey  County)  :  Cal.  State  Min.  Bur. 
Bull.  38,  p.  250;  Prel.  Kept.  7,  "p.  65;  Kept.  XXI,  pp.  29  and  57. 


NAPA   COUNTY. 


General   Features. 


Xapa  County,  witli  a  hind  area  of  783  square  miles,  runs  nearly  to  a 
point  at  both  extremities.  It  is  bounded  on  the  east  by  Solano  and 
Yolo  counties  and  on  the  west  by  Lake  and  Sonoma  counties.  Its 
southerly  end  touches  San  Francisco  Bay.  The  main  drainage  system 
of  the  county  is  that  of  the  Napa  Valley,  which  is  a  rich  agricultural 
section,  and  is  served  by  a  branch  line  of  the  Southern  Pacific  railroad, 
extending  from  San  Francisco  Bay  to  Calistoga,  in  the  northwestern 
corner  of  the  county.  Mt.  St.  Helena,  a  prominent  landmark,  is  in  the 
northwest  corner,  at  the  junction  with  Lake  and  Sonoma  counties. 

The  principal  geological  formations  in  the  county,  in  addition  to 
Recent  sediments  in  the  valleys,  are  Franciscan  (Jurassic)  slates,  sand- 
stones and  serpentine,  Miocene  sandstones  and  shales,  and  Tertiary 
voloanics.- 

The  in-incipal  mineral  resources  include  quicksilver,  inineral  water, 
miscellaneous  stone,  and  magnesite.  Occurrences  of  diatomite,  lime- 
stone, copper,  iron,  chromite,  gold,  silver,  and  mineral  paint  have  been 
noted.    A  cement  i)lant  at  one  time  operated  at  Napa  Junction. 

Clay    Resources. 

Common  clays  .suitable  for  brick  manufacture  occur  in  the  Napa 
Valley.      Previous  to  1890  there  was  a  plant  in  operation  near  Napa, 

1  Laizure.  C.  McK.,  op.  cit.,  p.   29. 

-  Smith,  J.  P.,  The  geological  formations  of  California  :  Cal.  State  Min.  Bur.  Bull. 
72,  and  Geological  Map. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


133 


where  brick  and  drain  tile  were  made.      The  cement  plant  at  Napa 
Jnnction  used  local  clay  in  cement  manufacture. 

An  interesting  occurrence  oi"  kaolin  is  described  at  considerable  length 
below,  not  so  much  for  its  present  value,  which  is  doubtful  in  the  pres- 
ent state  of  development,  but  because  of  its  significance  in  encouraging 
further  prospecting  for  commercial   deposits   in   tliis 


region. 


Clark  and  Mai\'ih  Kaolin  Mine.  This  property,  referred  to  in  a 
previous  report  ^  as  a  'china  clay'  deposit,  owned  by  W.  R.  Teale,  has 
been  acquired  by  J.  R.  Clark  and  C.  L.  Marsh  of  Calistoga.  The 
propertv  includes  the  following  areas:  S.^?,  SEj,  Sec.  12,  and  Ni  NE^, 
Sec.  13," T.  8  N.,  R.  7  W..  and  the  Si  SW],  Sec.  7,  NW^  NWj,  Sec.  18, 
and  the  diagonal  (NW.-SE.)  NEJ  5sE\  NW-1  Sec.  18,  in  T.  8  N.,  R.  6 
W.,  M.  D.  M.,  a  total  of  300  acres.  The  principal  workings  lie  near 
the  top  of  a  hill,  3.5  miles  by  road  south  of  Calistoga.  Some  road  grad- 
ing is  necessarv  before  trucks  can  be  run  to  the  mine. 


Photo  No.  27.  Clark  and  Marsh  Kaolin  Mine.  Main  workings,  facing  west. 
Note  scrub  brush  over  deposit,  and  timber  in  left  background  on  other 
formations.     Calistoga,  Napa  County. 

The  deposit  is  a  residual  kaolin  formed  by  the  alteration  of  a  rhyolitic 
rock  that  has  a  wide  distribution  in  the  region.  This  rock  forms  the 
crest  of  certain  of  the  low  hills  south  of  Calistoga,  and  is  distinguishable 
by  its  white  color,  and  its  hardness  at  the  surface,  where  silicification 
has  taken  place.  The  debris  covering  the  formation  is  very  thin,  and 
is  composed  of  irregular  grains  and  fragments  of  the  silicified  rock 
itself,  with  only  enough  soil  to  support  a  scattering  growth  of  shrubs, 
principally  manzanita,  w^hereas  the  soil  resulting  from  the  decomposi- 
tion of  most  of  the  other  formations  in  the  region  is  adequate  to  support 
a  growth  of  hea^7-  brush  and  trees.  This  characteristic  is  illustrated 
in  photo  No.  27,  wliicli  is  a  view  of  tlie  main  workings. 

Plate  VII  is  a  sketch  map  of  the  main  workings,  from  which  over  200 
tons  of  kaolin  have  been  removed,  some  of  which  has  been  shipped  to 

'Cal.  State  Min.  Bur.  Prel.  Kept.  No.  7,  p.  65,  1920. 


134 


DIVISION  OP  MINES  AND  MINING 


various  clay  products  manufacturers  for  testing.  An  examination  of 
the  -workings  shows  that  the  progress  of  kaolinization  has  been  very 
erratic.  The  hard,  silicified  zone  at  the  surface  is  from  one  to  three 
feet  thick.  Below  this,  the  kaolin  varies  from  a  non-plastic  aggregate 
of  partly-altered  feldspathic  grains,  to  a  fine-grained  mass  that  has 
fair  plasticity.  In  places,  following  lines  of  fracture,  the  kaolin  is 
heavily  stained  bj'  iron-bearing  minerals,  but  between  these  discolored 
areas,  the  mass  of  the  material  is  practically  w'hite  in  color.  The  most 
discouraging  feature  of  the  workings  is  that  most  of  the  headings  end 
in  material  that  is  badly  iron-stained.  It  is  estimated  that  20%  of  the 
material  exposed  in  the  underground  workings  is  contaminated  with 
iron.     The  iron-stained  portions  are  distributed  in  such  a  manner  as 


Plate  VII 


^/KETCH    MAP 

or 

CLAR/K-^'^'^  MARSH  KAOL/N M/NE 

CAL.'STOOA,   CAL/F. 


5<r»  L.  £• 

to 


ZO  Ft 


Uj 


to  make  hand-sorting  necessary,  rather  than  selective  mining,  if  the 
material  is  to  be  mined  on  a  commercial  scale.  The  writer  believes 
that  the  general  conditions  are  sufficiently  favorable  to  warrant  more 
extensive  prospecting  near  these  workings,  especially  at  greater  depths 
below  the  surface. 

From  a  point  alongside  a  road  about  1500  ft.  north  of  the  main 
workings,  and  at  an  elevation  400  feet  below  them,  is  a  72-ft.  tunnel, 
having  a  direction  of  S.  75°  W.  Most  of  the  material  encountered  in 
the  tunnel  is  well  kaolinized.  but  the  mass  of  the  material  is  slightly 
stained  with  iron.  The  best  kaolin  lies  near  the  floor  of  the  tunnel,  in 
that  portion  between  25  and  50  feet  from  the  portal.  Nearer  the  face, 
the  rock  is  not  so  well  decomposed,  and  there  is  a  large  proportion  of 
unaltered  quartz  and  feldspar.  It  is  possible  that  an  extensive  deposit 
of  kaolin  may  be  ^ou»d  b}^  farther  prospecting  in  this  locality.     No 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  185 

streaks  of  heavily  iron-stained  material  were  found  in  the  tunnel,  as  in 
the  workings  near  the  top  of  tlie  hill. 

This  deposit  of  kaolin  has  attracted  considerable  attention  in  the  past 
from  various  clay  products  manufacturers,  but  none  have  felt  war- 
ranted in  incurring  the  expense  of  leasing  or  purchasing  the  property, 
and  doing  a  sufficient  amount  of  prospecting  on  it  to  determine  the 
limits  of  workable  material.  It  is  one  of  the  few  localities  in  the  state 
where  high-grade  residual  kaolin  has  been  found,  and  it  is  more  accessi- 
ble to  marketing  centers  than  the  El  Cajon  IMountain  deposit  in  San 
Diego  County  oi-  the  deposits  at  Ilart,  San  Bernardino  County,  or 
even  tlie  sedimentary  deposit  on  the  Hunter  Raneli,  Orange  County. 

Sample  No.  190  is  representative  of  the  average  of  the  white  kaolin 
exposed  in  the  main  workings.  Sample  No.  191  is  from  the  same 
workings,  but  was  taken  from  the  iron-stained  portions  of  the  exposures. 
Sample  No.  192  was  taken  as  representative  of  the  average  white  kaolin 
from  the  lower  tunnel.     The  test  results  are  on  ])ages  261,  280  and  281. 

Bibl   (Clay  resources  of  Napa  Countv)  :   State  Min.  Bur.  Rept. 
XIV,  p.  262 ;  Prel.  Kept.  7,  p.  65. 

NEVADA   COUNTY. 
General   Features. 

Nevada  County  is  12  to  20  miles  wide  and  80  miles  long,  reacliing 
from  the  Sacramento  Valley  to  the  Nevada  line.  It  is  bounded  on  the 
north  by  Yuba  and  Sierra  counties,  on  the  east  by  the  state  of  Nevada, 
on  tlie  south  by  Placer,  and  on  the  west  by  Yuba  County.  It  contains 
974  square  miles,  and  its  population  is  10,860  (1920  census). 

The  mineral  production  of  the  county  is  mostly  gold  and  silver. 
Some  chromite,  copper,  granite,  lead,  and  miscellaneous  stone  are  also 
produced.  Antimony,  asbestos,  barytes,  clay,  gems,  iron,  mineral  paint, 
IXvrite,  soapstone,  and  tungsten  also  occur  in  the  county. 

Clay   Resources. 

Previous  publications  of  the  Bureau  ^  have  reported  several  clay 
deposits  from  the  vicinity  of  Grass  Valley,  Nevada  City  and  Colfax. 
Most  of  the  localities  mentioned  and  a  few  others  that  have  been  recently 
called  to  the  attention  of  the  Bureau  were  visited,  but  in  no  place  was 
found  a  deposit  of  high-grade  clay  that  would  warrant  exploitation 
under  any  commercial  conditions  that  are  likely  to  prevail  for  many 
years  to  come,  although  in  a  number  of  localities  common  brick  clay  of 
inferior  quality  occurs  and  in  at  least  one  locality,  on  the  Sonntag 
Ranch,  near  Peardale  (sample  No.  169),  a  buff -burning  clay  with  low 
shrinkage  and  fair  strength  was  found. 

The  geology  of  this  region  has  been  described  by  Lindgren  and 
others.-  The  few  deposits  of  clay-like  materials  occur  in  the  Tertiary 
superjacent  series  of  sedimentary  rocks  and  rhyolitic  flows,  and  in 
many   places   are   closely   associated   with   the   Neocene    gold-bearing 

'  Prel.  Rept.  No.  7,  p.  6a. 

=  Lindgren.  Waldemar,  The  Oold  Quartz  Veins  of  Nevada  City  and  Grass  Valley, 
California;    Seventeenth   Ann.   Rept.   U.    S.   Geol.    Survey,    Part   2,   pp. 1-262,    1896. 

Lindgren,  "Waldemar,  Tertiary  Gravels  of  the  Sierra  Nevada  of  California :  Prof. 
Paper  7.3,  U.  S.  Geol.   Survev,  pp.  121.  159,   1911. 

MacBovle,  Errol.  Mines  and  Mineral  Resources  of  Nevada  County:  State  Miner- 
alogist's Report  XVI,  Dec,  1918. 


136  DIVISION  OF  MINES  AND  MINING 

gravels.  One  of  the  most  typical  of  these  occurrences  is  the  altered 
rhyolitic  tuff  (sample  No.  172)  in  the  Manzanita  gravel  pit,  northeast 
of  Nevada  City.  This  is  commonly  described  as  'pipe  clay.'  It  is 
nearly  white  in  color  in  tlie  dry  state,  has  good  plasticity,  but  burns 
red  and  has  a  high  drying  and  firing  shrinkage.  Other  clays  sampled 
in  this  region  i)robably  are  variations  of  the  same  material,  but  mixed 
with  varying  proportions  of  decomposed  granite  and  other  products  of 
decomposition  of  the  bedrock  series.  In  general,  the  better  grade  of 
clays  differ  from  those  found  in  Placer  County  from  Alt  a  to  Gorge 
(page  158)  in  that  they  have  a  workable  plasticity  and  workable  firing 
properties,  whereas  all  of  the  volcanic  claj's  of  Placer  County  thus  far 
examined  seem  to  be  totally  unsuited  for  ceramic  uses. 

The  only  known  clay  occurrence  of  possbile  commercial  interest  in 
the  county  is  that  at  Pine  Hill,  described  below  under  Pine  Hill  Mine, 
and  John  Sweet  Kaolin  Deposit. 

Banner  Mountnin.  Sample  No.  170:  This  was  taken  from  near  the 
Banner  Mountain  road,  1.0  mile  east  from  the  intersection  with  the 
Nevada  City-Colfax  road,  in  or  near  the  NWi  NE^,  Sec.  30,  T.  16  N., 
R.  9  E.,  M.  D.  M.  This  probably  corresponds  to  the  deposit  formerly 
rei)orted  under  the  name  of  E.  M.  Taylor.^  The  present  owner  of  the 
adjoining  property  is  W.  E.  Parsons,  of  Grass  Valley.  No  develop- 
ment work  has  been  done,  but  the  deposit  can  be  traced  for  several 
hundred  feet,  and  is  at  least  six  feet  thick,  overlain  by  red  andesitic 
soil.  The  material  is  a  white  clay  shale,  and  the  sample  probably  con- 
tains more  iron  than  would  be  expected  in  the  mass  of  the  deposit,  away 
from  surface  contamination.     The  test  results  are  on  i)age  315. 

Beaser  Ranch,  Chicago  Park.  Sample  No.  168:  The  sample  Avas 
taken  from  an  undeveloped  deposit  on  the  P.  ]M.  Beaser  Ranch  in  the 
Si  Si  SWi,  Sec.  15,  T.  15  N.,  R.  9  E.,  M.  D.  M.  The  clay  is  exposed 
along  the  side  of  a  small  creek  bed.  The  extent  of  the  deposit  could 
not  be  determined,  but  it  is  at  least  two  to  three  feet  in  thickness,  and 
is  overlain  by  nonplastic  rhyolitic  tuff.  The  deposit  is  within  one-half 
mile  of  the  narrow  gage  railroad  connecting  Colfax  with  Grass  Valley. 
The  test  results  are  on  page  313. 

Manzanita  Mine.  Sample  No.  172:  This  is  a  sample  of  'i)ipe  clay' 
from  the  Manzanita  gravel  pit,  in  the  NE^  SW|,  Sec.  6,  T.  16  N., 
R.  9  E.,  M.  D.  M.,  1.5  miles  on  the  North  Bloomfield  road  from  the 
center  of  Nevada  City.  The  clay  occurs  in  beds  from  3  to  6  ft.  thick, 
interbedded  with  rhyolitic  sandstone  beds  of  approximately  the  same 
thickness.  The  total  thickness  of  rhyolitic  clay  and  interbedded  sand- 
stone is  approximately  90  feet.  This  formation  is  overlain  by  150  feet 
of  andesitic  tuffaceous  breccia,  and  is  underlain  by  190  ft.  of  Neocene 
gold-bearing  gravel,  which  in  turn  rests  on  the  granodiorite  bedrock. 
This  occurrence  and  that  represented  by  sample  No.  171  probably 
corresponds  to  the  occurrence  previously  described  as  lying  in  Sec.  6, 
T.  16  N.,  R.  9  E.,  near  the  Reddik  and'Odin  mines.-  The  test  results 
are  on  page  342. 

North  Bloomfield  Road.  Sample  No.  171:  This  sample  was  taken 
from  alongside  the  North  Bloomfield  Road,  1.8  mile  northeast  from 

'  Cal.    state    Min.    Bur.    Prel.   Kept.    No.    7,    p.    65. 
=  Op.    cit. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  137 

Nevada  City,  in  tlie  Wi  Sec.  6.  T.  16  N.,  R.  9  E.,  M.  D.  M.  The 
ownership  was  not  determined.  Alonp;  the  upper  side  of  the  road  at 
this  point  is  an  exposure  of  moderately  plastic,  fine-ofrained  clay,  nearly 
white  when  dry,  but  <»reenish  when  Avet.  The  bed  is  over  10  ft.  thick 
and  can  be  readily  traced  for  over  300  feet.  It  is  overlain  by  decom- 
jtosed  andesite.     The  test  results  are  on  pa«:e  329. 

The  Pi7}€  Hill  Mine,  now  controlled  by  Tra  J.  Coe,  462  Mills  Buildinp:, 
San  Francisco,  is  on  the  northern  half  of  Pine  Hill  in  Sec.  13,  T.  14  N., 
R.  7  E.,  M.  D.  M.,  one  mile  north  of  Wolf  Post  Office,  and  nine  miles 
by  road  to  a  proposed  railroad  siding  near  Auburn.  About  two-thirds 
of  this  distance  is  on  a  paved  highway.  The  property  comprises  160 
acres,  including  three  patented  claims,  the  Golden  Gate,  Golden  Gate 
Extension,  and  Thrasher. 

The  mine  was  originally  located  and  developed  as  a  copper  and  gold 
prospect.^ 

Several  well-defined  veins  have  been  found  on  the  property.  These 
contain  some  gold,  silver,  and  copper,  associated  with  quartz,  pyrite, 
and  limonite.  The  footwall  of  the  principal  vein  is  diabase,  and  the 
hanging  wall  is  serpentine.  Khyolite  and  iron-stained  porphyry  are 
found  in  places.  The  rocks  in  the  vicinity  of  the  veins  have  been 
altered,  and  considerable  kaolin  has  been  formed,  some  of  which  is 
moderately  pure.  Pour  sami)les  were  taken  from  various  points  in  the 
underground  workings. 


o* 


Sample  No.  159:  This  is  a  sample  of  nearly  white  kaolin  that  occurs 
as  a  gouge  in  a  vein  exposed  by  workings  on  the  west  side  of  Pine  Hill, 
near  its  crest.  At  this  point,  a  cross-cut  tunnel,  50  feet  long,  was  run 
to  cut  the  vein.  From  near  the  end  of  the  tunnel,  a  vertical  Avinze, 
26  feet  deep,  was  sunk',  which  was  continued  as  an  inclined  winze  in 
the  vein  which  has  a  dip  of  31°,  S.  35°  E.  The  inclined  winze  is  now 
filled  with  water  and  debris  to  within  60  feet  of  the  bottom  of  the  verti- 
cal winze,  so  that  the  total  depth  of  the  incline  could  not  be  determined. 
The  material  included  in  the  samiile  was  from  the  footwall  gouge  that 
is  expo.sed  in  the  incline  throughout  its  accessible  length.  It  was 
impossible  to  secure  a  sample  entirely  free  from  iron  staining  by  infil- 
tration from  the  overlying  pyritic  quartz,  as  the  workings  have  been 
open  for  many  years,  and  are  usually  flooded  to  the  floor  of  the  tunnel 
each  winter.  It  is  claimed  that  auger  holes  have  been  drilled  into  the 
footwall  to  a  depth  of  14  ft.  without  penetrating  the  kaolin,  and  that 
below  the  layer  of  surface  contamination,  the  kaolin  is  nniformly  Avhite 
in  color.  It  was  not  possible  to  verify  this  statement.  No  such  thick- 
ness is  exposed  in  the  cross-cut.  It  is  obvious  that  if  the  drill-holes 
had  not  been  drilled  at  right  angles  to  the  dip  of  the  vein,  false  indica- 
tions of  thickness  would  have  resulted.  Further  exploration  in  these 
workings  is  necessary  before  any  attempt  can  be  made  to  predict  the 
quantity  and  quality  of  kaolin  that  may  be  available.  The  test  results, 
page  261,  are  favorable,  but  not  as  satisfactory  as  to  color  as  in  sample 
No.  160. 

Sample  No.  160:  This  is  a  sample  from  the  lower  10  feet  of  a  50-ft. 
vertical  shaft  near  the  top  of  the  hill,  200  yards  or  more  east  of  the 

1  MacBoyle,  Errol,  Mines  and  Mineral  Resources  of  Nevada  County :  State  Miner- 
alogist's Report  XVI,  1921. 


138  DIVISION  OP  MINES  AND  MINING 

West  tunnel.  The  fired  color  and  other  ceramic  properties  of  this 
material  are  satisfactory^  for  man.y  high-grade  uses,  as  shown  on 
page  261,  and  the  occurrence  of  the  deposit  is  such  as  to  warrant  the 
prediction  that  a  commercial  tonnage  of  uniform  material  would  be 
disclosed  by  farther  development.  The  material  cut  by  the  first  40  ft. 
of  the  shaft  is  similar  in  ]ihysical  properties  and  in  mineralogical  con- 
stitution, but  is  light  pink  and  yellowish  in  dry  color,  showing  the 
presence  of  a  higher  proportion  of  iron  oxide. 

Sample  No.  166:  This  is  a  picked  sam])le  of  wliite  kaolin,  occurring 
as  a  gouge  in  a  vein  cut  by  a  tunnel  entering  the  North  side  of  the  hill, 
at  a  low  level.  The  gouge  is  from  two  to  four  feet  thick,  and  grades 
into  altered  country  rock,  similar  in  composition  to  sample  No.  167. 
The  continuity  and  homogeniety  of  this  occurrence  is  doubtful.  It  is 
unlikely  that  this  occurrence  will  be  of  importance,  as  continuity, 
homogeneity,  and  sufficient  thickness  for  economic  mining  may  be 
lacking.  The  test  results  are  given  on  page  316.  The  fired  color  is 
not  as  good  as  in  sample  No.  160,  and  the  fusion  point  is  considerably 
less. 

Sample  No.  167 :  This  is  a  composite  sample  from  a  cross-cut  branch 
of  the  East  tunnel.  It  is  typical  of  the  altered  country  rock  of  the 
hill,  and  occurs  in  abundance.  The  test  results  are  given  on  page  315. 
It  has  weak  plasticity. 

Bibl:  State  Mineralogist's  Report  XVI,  Nevada  County,  p.  S8. 

Sonntag  Fanrh,  PeardaJr.  Smnple  No.  169:  The  samjile  was  taken 
from  a  drainage  ditch  on  the  south  side  of  the  You  Bet  road,  1.8  mile 
from  Peardale  station  on  the  narrow  gage  railroad.  The  adjoining 
propertv  to  tlie  south  is  o-waied  by  H.  E.  Sonntag,  and  is  in  the  NE^, 
Sec.  3,  T.  15  N.,  R.  9  E.,  M.  D.  M.  At  this  point  a  bed  of  white  plastic 
clay  crosses  the  road  in  an  east-west  direction,  but  is  difficult  to  trace 
because  of  the  overlying  andesitic  debris,  which  weathers  to  a  red, 
plastic  soil  and  obscures  the  underlying  structure.  No  development 
work  has  been  done.  The  clay  bed  is  at  least  4  feet  thick.  The  sample 
was  taken  by  digging  a  hole  about  one  foot  deep  in  order  to  avoid 
contamination  from  the  andesite  soil  that  has  been  washed  over  the  out- 
crop, but  even  with  this  precaution,  the  sample  contains  more  iron- 
bearing  minerals  than  would  be  found  in  the  mass  of  the  deposit. 
Mr.  Sonntag  reports  that  the  same  clay  was  found  in  a  spring  on  his 
ranch  ^  mile  to  the  west,  but  this  could  not  be  verified.  It  is  not  certain 
whether  this  deposit,  or  the  one  from  which  sample  No.  168  was  secured,^ 
is  the  one  referred  to  in  previous  reports^  as  occurring  on  the  De  Golia 
Ranch.     The  test  results  are  on  page  313. 

John  Sweet  Kaolin  Deposit.  John  Sweet  of  Wolf  owns  the  south 
half  of  Pine  Hill,  consisting  of  120  acres  in  Sec.  13,  T.  14  N.,  R.  7  E., 
M.  D.  M.  The  same  formations  as  those  described  under  'Pine  Hill 
Mine'  persist  on  this  property,  but  very  little  development  has  been 
done.  A  30-ft.  vertical  sliaft  has  been  sunk  on  the  N^  NE^  of  the 
section,  but  this  was  not  accessible  at  the  time  of  visit  in  August,  1925. 
The  general  appearance  of  the  material  in  the  dump  at  this  shaft 

•  See  under  Beaser  Ranch,  ante. 

»Cal.   State  Min.  Bur.   Prel.  Kept.  No.   7,  p.   65, 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  139 

resembles  that  exposed  in  the  50-ft.  vertical  shaft  on  the  Pine  Hill 
property,  from  which  sample  No.  160  was  taken,  and  the  rather  meager 
evidence  available  points  to  the  conclusion  that  the  kaolin  was  formed 
by  the  alteration  of  a  diabase.  A  small  sample.  No.  158,  was  taken  of 
the  material  lying  on  the  dump,  but  was  not  tested. 

An  unsuccessful  search  was  made  for  the  deposits  previously 
described  at  Union  Hill,  and  that  in  Sec.  29,  T.  17  N.,  R.  9  E.,  M.  D.  M. 

Bibl    (Clav  resources  of  Nevada  County)  :  Cal.  State  Min.  Bur. 
Bull  38,'  pp.  217-218,  250-251;  Prel.  Kept.  No.  7,  pp.  65-66. 

ORANGE     COUNTY. 
General    Features.' 

Orange  County  is  bounded  on  the  east  by  Riverside  County,  north  by 
San  Bernardino  and  Los  Angeles  counties,  west  by  Los  Angeles  County 
and  the  Pacific  Ocean,  and  on  the  soutli  by  San  Diego  County.  It  com- 
prises 795  square  miles,  about  three-fifths  of  this  area  being  valley  land 
and  the  remaining  two-fiftlis  mountainous  and  foothill  land.  The  popu- 
lation of  tlie  county  is  61,375  (1920  census). 

The  Santa  Ana  Range  of  mountains  is  the  line  between  Orange  and 
San  Bernardino  counties,  at  the  northeast  corner  of  the  former  county. 
It  is  also  the  dividing  line  between  Orange  and  San  Diego  and  Riverside 
counties.  This  range  also  sends  up  a  line  of  foothills  westwardly  along 
the  seashore  nearly  half  way  across  the  county.  All  the  western  por- 
tion of  the  county  is  included  in  the  Santa  Ana  Valley.  The  highest 
point  of  land  has  an  elevation  of  5675  feet  above  sea  level,  and  is  known 
as  Santa  Ana  Peak. 

The  Santa  Ana  River  comes  into  the  county  near  the  northeast  corner 
and  continues  through  it  in  a  northwesterly  direction,  flowing  into  New- 
port Bay.  Santiago  Creek  has  its  rise  in  the  Santa  Ana  Range  of 
mountains,  and  flows  in  a  northerly  and  westerly  direction,  emptying 
into  the  Santa  Ana  River  about  two  miles  northwest  of  the  city  of 
Santa  Ana.  Aliso  Creek  has  its  rise  in  the  same  range,  but  on  the 
southern  slope  of  the  mountains,  and  runs  in  a  southwesterly  direction, 
flowing  into  the  ocean  near  Arch  Beach,  about  twenty  miles  southeast  of 
the  mouth  of  the  Santa  Ana  River.  Trabuco,  Mission  Vie  jo,  and  San 
Juan  creeks  have  their  rise  on  the  south  side  of  the  Santa  Ana  Range 
and  come  together  near  the  sea,  reaching  the  ocean  at  'San  Juan-by-the- 
Sea.'     Coyote  Creek  marks  the  boundary  of  the  county  on  the  west. 

Geology. 

The  formations  of  the  region  consist  of  a  base  of  granitic  and 
metamorphic  rocks  overlain  by  Cretaceous,  Tertiary,  and  Pleistocene 
sediments. 

The  main  portion  of  the  Santa  Ana  Mountains  is  composed  of  ancient 
crystalline  rocks,  mostly  slates  of  Jurassic  age ;  along  the  western  and 
southern  flanks,  rocks  of  Chico  age  are  exposed,  which  in  turn  are  over- 
lain by  small  patches  of  the  Eocene.  In  the  Laguna  Hills  the  formations 
exposed  are  mainly  coarse  sandstone  of  Eocene  age.  These  are  overlain 
along  the  edges  of  the  hills  by  beds  of  sandstone  and  sh^le  of  the  Mon- 
terey series.     In  the  flat  area  running  from  Tustin  to  El  Toro  the  dia- 


1  Tucker,  Vi".  B.,  Orange  County:  State  Mineralogist's  Report  XXI,  pp.  58-59,  1925. 


140  DIVISION  OF  MINES  AND  MINING 

tomaeeous  shale  of  the  IMonterey  series  is  present,  occupying  a  synclinal 
ti-ouuii  between  the  Santa  Ana  ^Mountains  and  the  Lagnna  Hills.  This 
condition  continues  southeast  through  the  Capistrano  district  to  the 
San  Diego  County  line. 

For  detailed  geology  of  Orange  County  the  reader  is  referred  to  the 
reports  by  Bowers  ^  and  Fairbanks-  in  two  of  the  earlier  State 
^Mineralogist's  Reports. 

Orange  County  is  among  the  upper  three  counties  in  California  in 
the  value  of  its  mineral  production,  the  other  two  being  Los  Angeles 
(first  in  1926)  and  Kern  (second  in  1926)  counties.  In  all  three  cases, 
the  principal  product  is  petroleum.  Of  secondary  importance  in  Orange 
County  are  natural  gas,  miscellaneous  stone,  clay,  brick,  gold,  silver, 
copper,  lead,  and  zinc.  Besides  these  substances,  occurrences  of  coal, 
gypsum,  diatomite,  sandstone,  and  tourmaline  have  been  found  in 
Orange  County. 

Clay   Resources. 

Low-grade  clays  for  use  in  making  red-burned  structural  ware  are 
fairly  abundant  in  the  county,  and  plants  seeking  a  location  need  have 
no  difficulty  in  finding  suitable  material. 

On  the  w^est  side  of  the  Santa  Ana  Range  are  deposits  of  high-grade 
clay  that  are  apparently  equal  in  geological  age  to  the  Eocene  clays  of 
the  Temescal  Valley  (Alberhill-Corona  district)  in  Riverside  County. 
These  deposits  have  been  developed  in  recent  years,  and  a  number  of 
exceptionally  good  varieties  of  fireclay  are  now  being  produced  com- 
mercially. An  especially  interesting  occurrence  of  flint  fireclay  occurs 
on  the  Goat  Ranch,  in  Santa  Ana  Canyon,  in  the  Upper  Chico  (Upper 
Cretaceous)  formation. 

American  Silica  Company.  G.  Ray  Boggs,  president.  Office,  Suite 
1212  Pacific  Mutual  Building,  Los  Angeles.  This  company  controls 
an  important  deposit  of  fireclay  on  the  Hunter  and  Robinson  ranches, 
12  miles  by  road  east  of  the  town  of  El  Toro.  The  Hunter  Ranch  lies 
in  Sec.  11,'t.  6  S.,  R.  7  W.,  S.  B.  M.,  and  the  Robinson  Ranch  is  adjoin- 
ing. At  the  time  the  property  was  visited,  in  August,  1925,  some  1500 
tons  of  clay  had  been  mined  from  two  different  openings.  Two  samples 
were  taken,  No.  63  and  64.  The  test  results  are  on  ]iage  260.  Since 
1925,  the  property  has  been  extensively  developed,  and  new  deposits  of 
valuable  fireclays  have  been  discovered,  hence  a  description  of  the 
earlier  developments  is  of  little  value  at  this  time.  Through  the  cour- 
tesy of  Mr.  Boggs,  several  samples  of  the  clay  that  was  in  use  in  1926 
were  secured,  both  as  crude  clay,  and  in  mixes  that  were  ]irepared  for 
the  manufacture  of  fire  brick.  See  samples  No.  266,  268  and  270,  on 
liages  292.  260  and  282.  respectively. 

The  clays  are  probably  of  Eocene  age. 

Brea  Clay  Products  Company.  C.  M.  Haaker,  president;  A.  D. 
Yost,  superintendent.  Home  office,  Brea.  The  plant  is  on  the  eastern 
side  of  the  town  of  Brea. 

Operations  commenced  in  the  summer  of  1925.  Common  red  brick 
is  manufactured  fro]ii  local  surface  clay  which  is  mined  to  a  depth  of 

^Bowers,  Stephen,  Orange  County :  State  Mineralogist's  Report  X,  pp.  399-409, 
1890. 

=  Fairbanks,  H.  W.,  Geology  of  San  Diego  County :  also  portions  of  Orange  and 
San  Bernardino  counties:   State  Mineralogist's  Report  XI,  pp.  113-118,  1893. 


1 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  141 

10  to  12  feet  with  a  steam  shovel.  A  drag-line  eonveyor  delivers  tlie 
elay  to  a  belt  eonveyor  Avhieh  feeds  a  png-iiiill  and  aiifjer  machine, 
equipped  with  a  hand  operated  side  cutter.  After  drying;  in  the  open 
and  under  sheds,  the  brick  are  fired  in  open  oil-fired  field  kilns.  A 
semi-Diesel  engine  is  used  for  operating  the  i)lant. 

The  output  at  the  time  of  visit  in  July,  1925,  was  60,000  brick  per 
day,  and  an  increase  to  80,000  was  expected  within  a  short  time.  The 
company  also  expected  to  i)roduce  hollow  tile  and  roofing  tile. 

lSam])h>  Xo.  6;")  was  taken  for  testing.     See  page  322. 

Garhn-  Brick  and  Tile  Co.  II.  Garber,  president,  Olive.  The  com- 
pany controls  6  acres,  one-half  mile  east  of  Olive,  on  the  Orange  County 
Park  road.  Common  brick,  hand-made  roofing  tile,  floor  tile,  roof 
dressing  and  a  dust  product  for  molding  sand  are  manufactured. 

All  of  the  clay  used  is  mined  from  a  pit  on  the  property.  Material 
is  transported  from  the  clay  pit  by  a  drag  scraper  to  the  plant,  where 
it  passes  through  rolls,  is  elevated  to  storage  bins.  The  brick  are  made 
by  the  soft  mud  process.  A  pug-mill  prepares  the  clay  for  the  brick 
press  as  well  as  for  the  tile  plant.  The  brick  are  conveyed  by  a  cable 
convej-or  to  drying  racks.  After  drj'ing,  the  brick  are  burned  in  field 
kilns,  using  natural  gas  as  fuel. 

Both  roof  and  floor  tile  are  hand  molded,  air  dried  under  sheds,  and 
fired  in  two  down-draft  kilns.  The  rated  output  of  the  plant  is  2000 
roof  tile  and  25,000  brick  per  day.  The  ecpiipment  includes  a  30-h.p. 
boiler,  Ingersoll-Rand  compressor,  Blake  type  crusher,  screens  and 
elevators.     From  25  to  30  men  are  employed. 

Bibl:  State  Mineralogist's  Report  XXI,  p.  65. 

Gladding,  McBean  and  Company.  Office  of  Southern  Division  at 
621  South  Hope  Street,  Los  Angeles.  This  company,  through  its  merger 
with  the  Los  Angeles  Pressed  Brick  Com))any,  now  owns  the  Goat 
Ranch,  noted  in  previous  reports^  as  containing  an  important  deposit 
of  flint  fireclay.  The  location  of  tiie  property  is  shown  on  Plate  X, 
under  Riverside  County.  The  property  consists  of  1700  acres,  and  lies 
in  an  extremely  rugged  portion  of  the  Santa  Ana  ^Mountains,  south  of 
Gypsum  station  on  the  Santa  Pe  i-ailroad.  The  deposit  lay  idle  for 
many  years,  but  since  1925  considerable  development  work  has  been 
done,  which  has  demonstrated  the  presence  of  large  deposits  of  flint 
fireclay  and  red-burning  shale  in  the  Upper  Chico  (Upper  Cretaceous) 
formation.  A  view  of  one  of  the  fireclay  exposures  is  shown  on  ])hoto 
Xo.  28,  and  one  of  the  red  shale  prospect  pits  is  illustrated  on  photo 
No.  29. 

The  flint  fireclay,  when  dry,  is  gray  to  black  in  color,  and  has  a 
conelioidal  fraetur(\  The  lighter-colored  varieties  have  very  much  the 
appearance  of  chert,  but  can  easily  be  scratched  with  a  knife,  and  when 
ground  with  water,  develop  moderate  plasticity.-  It  contains  from 
34%  to  40%  of  alumina,  and  is  highly  refractory.  Sample  No. 
282  was  taken  for  testing,  but  should  not  be  considered  as  representative 
of  the  deposit,  as  it  is  a  grab  sample  from  development  workings.  The 
results  are  on  page  282.    Sample  No.  221  (page  330)  of  similar  material, 

1  Prel.  Rept.  7,  p.  66,  and  Rept.  XXI,  p.  66.  Listed  under  "Los  Angeles  Pressed 
Brick  Companv." 

-  In  this  connection,  see  Walker,  T.  C,  The  Effect  of  Pine  Grinding  on  an  Indurated 
Clay:  Jour.  Amer.  Cer.  Soc,  Vol.   10,  pp.  449-450,  June,   1927. 


142 


DIVISION  OP  MINES  AND  MININO 


but  of  much  poorer  quality  and  containing  a  high  percentage  of  iron, 
was  also  tevSted. 

The  red-burning  shale  has  been  prospected  at  a  number  of  points 
on  the  property.     It  is  of  value  in  the  manufacture  of  red-burned  vitri- 


■•^ 


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A\ 


f^. 


t 

X 


I 


Photo  No.  2S.  Flint  fire  clay  at  iiortal  of  tunnel,  Goat 
Ranch,  Gladding.  McBean  and  Company,  Orange  County. 
(Sample  No.   282.) 

tied  ware,  such  as  sewer  j)ipe  and  paving  brick.     ISample  Xo.  223   (p. 
343)  was  taken  and  tested. 

La  Bolsa  Tile  Company.     G.  W.  Moore,  president ;  A.  W.  Griffith, 
secretary  and  manager ;  E.  R.  Bradbury,  superintendent.     Home  office, 


CLAY  tTESOURCES  AND  CERAMIC  INDUSTRY 


143 


Huntington  Beach.  This  company  lias  been  established  for  twenty 
years.  The  j)lant  anci  clay  pit  are  two  miles  north  of  Huntington 
Beach  at  Weibling  siding  on  the  Soutliern  Pacific  Railway,  adjoining 
the  northern  edge  of  the  Huntington  Beach  oil  field.     The  company 


r'^ 

-v'    '*    ^^W^- 

^^m^ljmMXi-  ■ 

r 

^^™gi.  !U9.Jim^ 

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^^^^^^^^^^^^|Q|7   Jc 

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Photo  No.  29.     M  -M  2  pit,  Goat  Ranch,  Gladding,  McBean  and  Company, 

Orange  County. 


Photo  No.   .30.     Plant  of  La  Bolsa   Tile  Company,  Weililinp,    Orange  County. 
(From  State  Mineralogist's  Report  XXI,  p.   65,   1925.) 

o^\Tis  31  acres  in  Sec.  35,  T.  5  S.,  R.  11  W.,  S.  B.  M.  The  products  are 
drain  tile  from  3  to  20  inches  in  diameter,  hollow  building  blocks, 
common  brick,  and  more  recently,  ruffled  face  brick.  Photo  No.  30  is  a 
view  of  the  plant. 


144  DIVISION  OP  MINES  AND  MINING 

The  cl;i,y  is  iiiiiicd  lo  a  (l('i)th  of  five  feet  by  a  Pordson  tractor,  using 
a  harrow  for  loosening  and  a  scraper  to  deliver  it  to  a  hopper,  which 
feeds  a  dry  pan.  An  elevator  delivers  tlie  ground  material  to  a  hopper 
which  feeds  a  short  inig-niill  from  which  the  clay  passes  to  an  auger 
machine.  The  plant  is  equipped  with  two  auger  machines  which  are 
used  to  shape  all  products  except  drain  tile  of  10  inches  diameter  or 
larger,  for  which  purpose  a  vertical  steam  press  is  used. 

The  drying  sheds  are  heated  by  hot  air  forced  by  a  blower  through 
flues  under  the  floor.  The  air  is  heated  either  by  the  exhaust  from  the 
kilns  or  by  exhaust  steam.  Tlie  drying  sheds  have  a  storage  capacity 
of  60,000  tile.  The  drying  cycle  is  from  24  to  over  60  hours,  depending 
on  tlie  size  of  the  ware. 

The  plant  is  equipped  with  three  28-ft.  down-draft  kilns,  with  a 
capacity  of  70  to  80  tons  of  material  each,  and  one  32-ft.  kiln,  with  a 
capacity  of  100  tons.  Natural  gas  is  generally  used  as  fuel,  but  the 
plant  is  equipped  for  oil  firing  when  needed.  The  firing  cycle  is  72  to 
80  hours  to  a  maximum  of  1650°  F. 

The  finished  products  are  dense  and  hard  with  a  good  red  color.  Ten 
men  are  employed. 

Bibl:  State  Mineralogist's  Report  XXI,  p.  66;  Prel.  Rept.  No.  7, 
p.  66. 

Olive  Roofing  Tile  Co.  Ramon  Flores,  owner.  This  is  a  small  plant 
near  that  of  the  Garber  Brick  antl  Tile  Com})any.  Hand-made  roofing 
tile  is  the  only  product.  Surface  clay  from  the  property  is  utilized. 
One  kiln  is  in  use. 

The  plant  is  a  Mexican  operation,  and  as  many  as  24  men  are 
employed  at  times. 

Orange  County  Brick  and  Tile  Company}  F.  C.  Krause,  president; 
Charles  Page,  secretary;  W.  J.  Carmichael,  general  manager.  The 
company  owns  nine  acres  in  Sec.  9,  T.  4  S.,  R.  10  W.,  within  the  city 
limits  of  Anaheim. 

The  company  is  manufacturing  building  brick,  and  also  produces 
sand  for  building  purposes.  The  material  used  is  unconsolidated  sand. 
The  sand  is  mixed  with  lime  and  cement  in  the  following  proportions : 
Common  brick:  lime  7|%,  cement  2%.  Face  brick:  lime  10%, 
cement  5%. 

Material  from  the  sand  ])it  is  transported  by  drag-line  scraper  to  a 
hopper,  from  Avhich  it  goes  to  a  })ucket  elevator,  elevated  and  then 
])assed  through  a  revolving  screen.  Here  it  is  sized  into  three  different 
sizes ;  the  over-size  and  the  minus  8-mesh  going  to  storage  bins,  the  fine 
sand  to  wet-grinding  pan,  where  it  is  ground  and  then  elevated  to  two 
bins,  then  sent  on  to  the  mixer  from  which  it  is  fed  to  two  American 
clay  brick  rotary  presses.  One  press  has  a  capacity  of  8000  brick,  the 
other  17,000  brick.  The  brick  then  are  loaded  on  to  cars  and  given 
10-hour  heat  treatment  under  125  pounds  pressure  in  two  Hardinge 
cylinder  driers.  Tliese  driers  are  80  feet  long  by  6  feet  in  diameter. 
Heat  for  cylinder  driers  is  furnished  by  70-h.p.  boiler,  oil  being  used 
as  fuel.  The  other  equipment  is  driven  by  electric  motors.  Ten  men 
are  employed. 

^  By  W.  B.  Tucker,  07;.  cit.,  p.  60.     While  not  a  ceramic  operation  of  the  type  being 
con-^iidered   in  this  report,   this  descriiition   i.s  included  here  as  of  general    interest,   " 
it    is   tvnical   of  similar   cjpeT'ations   in   various   parts  of  the   state. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


145 


The  Vitrefrax  Company  (O'Neill  Ranch  Fire  Clay  Deposit).  On 
the  Raiiclio  de  Santa  ^Farj^arita,  the  <>reater  portion  of  -wliich  is  now 
owned  by  the  Jerome  O'Neill  I'aiiiily,  are  several  excellent  showings  of 
high-grade  fireclay,  one  of  which  has  been  leased  and  developed  within 
the  last  few  j^ears  through  the  efforts  of  the  Vitrefrax  Company  of  Los 
Angeles.  This  deposit  is  10.2  miles  by  i-oad  east  of  San  Juan  Capis- 
trano,  in  Gabino  Canon,  close  to  the  San  Diego  County  line.  The 
material  consists  of  a  white  and  blue-gray  fireclay  high  in  alumina, 
and  quite  free  from  ii'on  stains.  It  is  known  locally  as  a  bone  clay, 
and  in  fact  corresponds  in  analysis  to  that  of  typical  bone  clays,  but 
without  the  distinctive  jiisolitic  structure  of  the  type  clays.  The  fire- 
clay bed  is  overlain  by  a  thin  bed  of  black  carbonaceous  ])lastic  clay, 
which  separates  it  from  the  overlying  loosely  con.solidated  sandstone. 
Underlying  tlie  fireclay  is  a  mottled  ])lastic  clay,  similar  in  general 
appearance  to  the  Alberhill  i)ink-mottled  variety.     The  thickness  of  the 


Photo    No.    ;>1.     Vitrefrax    Co.      Entrance    to   upper    chamber    workings,    O'Neill 
Ranch  clay  depo.sit.  Orange  County.      (Sample  No.   62.) 

fireclay,  as  exposed  in  the  workings,  is  from  10  to  15  feet.  The  bed  is 
flat-lying,  with  a  slight  westerly  dip.  A  view  of  the  deposit  is  shown 
on  plioto  No.  31. 

The  clay  is  recovered  by  chamber  mining,  using  posts  where  needed 
to  support  the  overburden.  At  the  time  of  visit,  in  July,  1925,  an 
area  of  70  by  25  feet  had  been  mined  and  a  100-foot  tunnel  had  been 
driven  to  the  west  of  the  chambers,  and  at  a  lower  level,  with  the  object 
of  providing  for  gravity  loading  of  small  mine  cars,  by  means  of  a 
raise  to  the  clay  bed.  One  of  these  raises  had  been  driven  nearly  to 
the  roof  of  the  clay,  and  demonstrated  that  the  total  thickness  of  clay 
above  the  tunnel  is  nearly  20  feet. 

At  several  other  localities  in  the  vicinity  are  exposures  of  various 
grades  of  clay.  It  is  likely  that  in  the  future,  important  clay  beds  will 
be  developed  and  mined. 

10 — 54979 


146  DIVISION  OF  MINES  AND  MINING 

Samjile  No.  62  was  taken  for  testing.     See  page  259. 

Bibl  (Clay  resources  of  Orange  County)  :  Repts.  XV,  519;  XXI, 
pp.  65-67.     Prel.  Kept.  7,  j)]).  66-67. 

PLACER   COUNTY. 
General    Features.' 

Placer  County  extends  from  the  Sacramento  Valley  on  the  west  for 
a  distance  of  80  miles  to  the  Nevada  state  line  on  the  eastern  slope  of 
the  Sierra  Nevada,  including  the  larger  part  of  Lake  Tahoe.  The  total 
area  is  1395  square  miles.  The  elevation  increases  gradually  from  near 
sea  level  on  the  west  to  mountain  peaks  8000  to  9000  feet  high  along  the 
summit  of  the  range  on  the  east,  then  descends  to  6225  feet  along  Lake 
Tahoe.  There  is  a  corresponding  variation  in  climatic  conditions.  The 
western  part  of  the  count}'  below  an  elevation  of  2500  feet  supports 
most  of  its  industries  and  nearly  all  of  the  population  of  about  20,000. 
In  this  region  snow  seldom  falls  below  2000  feet  elevation  and  never 
lies  on  the  ground  below  that  elevation.  The  county  seat,  Auburn,  is 
at  an  elevation  of  1360  feet,  and  the  di.strict  from  there  westward 
through  Newcastle,  Penryn,  Loomis  and  Rocklin  is  the  most  important 
deciduous  fruit  producing  area  in  the  state,  Newcastle  being  the  leading 
shipping  point.  The  soil  is  mainly  decomposed  granite  and  granodiorite 
on  the  west  and  amphibolite  schist  and  diabase  near  Auburn  and  to  the 
east,  until  the  granodiorite  of  the  high  mountains  is  reached. 

The  Ogden  route  of  the  Southern  Pacific  system  traverses  the  county 
from  the  Sacramento  line  to  the  summit  of  the  Sierra  Nevada,  passing 
through  the  principal  towns,  and  the  Oregon  branch  of  the  same  rail- 
road, leaving  the  main  line  at  Roseville,  passes  northward  through  Lin- 
coln, serving  the  farming  and  clay  Avorking  industries  there.  Two  state 
highways  run  about  parallel  to  the  two  lines  of  railroad,  one  eastward 
from  Sacramento  over  the  mountains,  and  the  other  northward  from 
Roseville  along  the  east  side  of  Sacramento  Valley.  A  third  state  high- 
way runs  north  from  Auburn  to  Grass  Valley  and  Nevada  City,  in 
Nevada  County. 

Taking  its  name  from  the  Spanish,  because  of  the  richness  of  its  sur- 
face gold  placers,  the  county  showed  a  great  diversity  of  mineral 
resources  at  an  early  date,  and  was  distinctly  a  mining  county  until 
about  1890,  when  fruit  raising  began  on  a  large  scale  for  eastern  ship- 
ment. Lumbering  and  the  summer  grazing  of  cattle  in  the  higher 
mountains  have  been  less  important  industries. 

Gold  has  been  the  principal  mineral  ]n-oduct  of  the  county,  but  since 
1920  the  value  of  the  pottery  clay  and  brick  production  has  exceeded 
that  of  the  gold  production.  Since  1922,  the  value  of  pottery  clay  alone 
has  been  greater  than  that  of  gold.  Other  mineral  products  that  have 
been  produced  commercially  in  recent  years  include  miscellaneous  stone, 
granite,  silica  (quartz),  chromite  and  copi)er.  Small  tonnages  of 
asbestos,  manganese  ore,  magnesite,  mineral  paint  and  soapstone  have 
been  shipped  at  various  times,  and  the  limestone  production  of  the 
county  was  at  one  time  of  importance. 

Clay   Resources. 

A  remnant  of  the  lone  formation,  containing  valuable  clay  deposits, 
occurs  on  the  edge  of  the  Sacramento  Valley  at  Lincoln.      Since  1875, 


>  Logan.  C.  A.,  State  Mineralogist's  Kept.  XXIII,  pp.  235-237,  1927, 


CLAY  RESOURCES  AND  CERA:\riC  INDUSTRY  147 

this  area  lias  been  a  elay  produeiii^'  and  clay  woi'kin*;  center.  Present 
prodnction  from  the  district  is  between  12;"), ()()()  and  ir)(),0()0  tons 
annnally.  Other  remnants  of  the  lone  foi-mation  occnr  at  varions  ])laees 
in  the  county,  ami  cla\s  have  been  found  in  other  formations,  but  none 
of  these  have  led  to  the  discovery  of  commercial  deposits.  On  account 
of  the  fact  that  the  active  clay  workinji;  industry  centers  about  Lincoln, 
the  discussion  of  the  elay  resources  of  the  county  is  divided  into  two 
sections:  the  Lincoln  District,  and  ^liseellancons  Deposits. 

Lincoln  District. 

At  Lincoln  is  one  of  the  three  most  inipoHant  clay  dejiosits  in  the 
state.  The  deposits  undei-lie  a  fjroup  of  low  hills  that  rise  to  a  maxi- 
mum of  80  feet  above  the  alluvial  jilain  of  the  Sacramento  Valley.  The 
clays  are  a  remnant  of  the  lone  formation  which  was  jirotected  from 
erosion  by  a  capping  of  andesite-agglomerate.  As  shown  by  C.  N. 
Schuette,^  and  illustrated  in  the  vertical  section  through  a  portion  of 
the  jiroperty  of  the  Clay  Cor])()i-ation  of  Califoinia,  |)late  IX,  the  upi)er 
clay  beds  have  been  removed  by  erosion  a  short  distance  beyond  the 
limits  of  the  ])resent  lava  cap.  Since  the  i)eriod  of  erosion,  gravel, 
sand,  and  soil  from  the  rivers  and  flood  plains  of  the  Sacramento  Valley 
have  raised  the  floor  of  the  valley  to  its  present  level. 

In  some  ])laces  the  recent  dej^osits  abut  against  the  margin  of  the 
lava  cap,  and  in  other  {)laces  they  lie  against  the  gently-slo])ing  surface 
of  erosion  of  the  uj)])er  clay  beds,  thus  affording  some  exposures  of 
elay  which  aided  in  the  original  discovery  and  development  of  the 
de])0sits. 

The  clay  beds  lie  ])ractically  hori;^ontal,  and  are  characterized  by 
remarkable  uniformity  in  thickness  and  quality-  over  large  areas. 
Several  different  beds  can  be  differentiated  and  are  of  sufficient  thick- 
ness to  permit  separate  mining.  The  ceramic  ])roperties  of  the  clays 
may  be  summarized  as  follows:  The  drying  and  fii-ing  shrinkage  is 
high,  but  shrinkage  takes  })lace  with  little  danger  of  cracking.  The 
fusion  point  lies  between  cone  28  and  cone  33 ;  fired  colors  range  from 
light  buff  to  light  red;  knife  hardness  develo])s  near  cone  1;  vitrifica- 
tion is  well  advanced  (less  than  3';>  absorption)  at  cone  13;  and  fired 
strengths  are  good,  but  with  the  highly-grogged  mixtures  necessary  to 
avoid  excessive  shrinkage,  the  body  strength  may  not  be  so  high  as  is 
desired.  The  princijial  uses  are  for  architectural  terra  cotta,  fire  brick 
and  stoneware. 

Clay  Corporation  of  California,  .lolin  T.  Koberts,  ])resident.  Home 
office,  Kialto  Building,  San  Francisco.  The  mining  property  of  the 
Clay  Corporation  of  California,  a  subsidiary  of  the  Stockton  Fire  Brick 
Company,  has  recently  been  described  by  C.  N.  Schuette.-  The  descrip- 
tion that  follows  is  ])artly  based  on  ^Mr.  Schuette 's  article,  and  partly 
upon  notes  made  by  the  Avriter  when  the  property  was  visited  on 
August  13,  1925,  and  again  on  June  25,  1926. 

The  property  is  in  Sec.  4  and  9,  T.  12  N.,  R.  6  E.,  M.  D.  M.  The 
area  is  covered  by  andesite-agglomerate  from  its  southern  boundary  to 

■  Engineering  Principles  Applied  to  Exploitation  of  a  Clay  Deposit,  Eng.  and  Min. 
Jour.-Press.  Vol.  121,  p.  964,  June  12,  1926. 
-  Op.  cit. 


148 


DIVISION  OF  MIXES  AND  MINING 


Plate    VIII.       General    arrangement    of    quarry    and    plant    of    the    Clay 
Corporation    of    California,    Lincoln,    Placer    County.  (Reprinted 

by   i)erniission  of  Engineering  and  Mining  Journal.) 


I 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


14U 


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O  o 


X 


150 


DIVISION  OP  MINES  AND  MINING 


a  line  roiij;lily  i)ar;illel  to  and  ai)i)roximately  1600  ft.  north  of  the 
Lineoln-Marysville  ]ii<>'hway.  Drilliiiji'  and  test  ))ittin^'  shows  that  all 
of  tlio  chiy  beds  exposed  in  tlie  adjoining  property  of  the  Lincoln  Clay 
Prodncts  Co.  on  the  south  ])ersist  on  an  even  grade,  thickness,  and 
character  under  the  area  covered  by  the  lava  flow,  but  that  they  do  not 
])ersist  northward  as  they  had  been  removed  by  erosion  before  the 
deposition  of  the  valk\y  sediments.  This  condition  is  shown  in  the 
generalized  north-and-south  cross-section,  plate  9.  Over  1,000,000  tons 
of  clay  corresponding  to  the  Lincoln  Clay  Products  Co.  No.  1-6,  have 
been  developed. 

The  general  arrangement  of  the  quarry  and  i)lant  is  shown  on  plate 
VIII.  Since  the  stripping  is  as  thick  or  thicker  than  the  underlying 
clay,  the  trackage  was  laid  out  to  place  the  waste  dump  as  near  the  pit  as 
possible.  The  quarry  starts  on  the  north  slope  of  the  hill  and  is  carried 
parallel  to  the  trend  of  the  hill,  thus  giving  a  pit  face  of  sufficient 


Photo  No.   32.     End-cut  during  preparation  of  pit  of  Clay  Corporation  of  Cali- 
fornia, at  Lincoln,  Placer  County.      (Samples  No.  152  and  153.) 

length  to  yield  a  full  season's  tonnage  at  one  cut.  The  pit  face  is  1700 
feet  long.  , 

The  ])it  equi])ment  consists  of  a  f-cu.  yd.  gasoline  shovel,  an  8-ton 
gasoline  locomotive,  ten  8-yd.  rocker  dump  cars,  and  two  flat  cars. 
Thirty-])ound  rail  and  o6-in.  track  grade  is  used,  with  a  maximum  of 
2%  grade.  Photo  No.  32  shows  the  shovel  at  work  during  the  prepara- 
tion of  the  pit. 

Tlie  clay  storage  ])lant  was  designed  with  the  object  of  .securing  a 
thorough  mixing  of  the  clay  as  received  from  the  pit,  and  to  remove  as 
much  water  as  possible  before  sliipping.  The  clay  is  crushed  to  2^  in. 
in  a  21  by  42  in.  single-roll  crusher.  The  crusher  discharge  is  carried 
by  an  IS-in.  belt  conveyor  to  llie  top  of  tlie  storage  building,  where  it  is 
spread  in  a  lliin  layer  over  the  surface  of  llie  bin  by  a  self-propelled, 
self-reversing  1rii)])er.  Drying  by  the  hot  summer  air  sweej)ing  tlirough 
the  building  is  very  etfective.  A  concrete  reclaiming  tunnel  under  the 
floor  of  the  storage  building  is  equipped  with  hand-operated  gates  to 


I 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  151 

dischar^^e  the  clay  to  an  18-in.  belt  conveyor,  which  carries  it  to  a  cross- 
tunnel  at  one  end  of  the  building,  where  the  clay  is  delivered  to  an 
inclined-belt  conveyor,  18  in.  wide,  running  up  to  the  top  of  the  three 
oO-ton  storage  bins  in  the  mill  building. 

From  the  end  bin  the  clay  can  be  drawn  directly  into  railroad  cars 
on  the  spur  track.  PVoni  either  or  all  of  the  bins,  the  clay  can  be  fed 
by  apron  feeders  to  a  chute  leading  to  a  five-roller  low-side  Raymond 
mill.  The  ])ulverized  clay  is  blown  to  a  cyclone  collector  in  the  toj)  of 
the  mill  building,  and  is  delivered  to  any  one  of  three  -lO-ton  bins,  which 
are  fitted  with  three  sacking  spouts  each.  The  sacked  clay  is  stored  in 
the  building  while  awaiting  shipment. 

The  pit  is  o])erated  in  the  dry  season  between  ]\Iay  and  December. 
The  minimum  operating  force  consists  of  the  superintendent,  two  men 
on  the  shovel,  two  men  on  haulage,  and  two  men  to  operate  the  plant. 
Two  or  three  extra  men  may  be  required  from  time  to  time,  and  at  the 
beginning  of  the  season  a  track  gang  is  employed  for  two  weeks  to 
prepare  the  track  for  the  season's  operation.  Two  men  attend  to 
shi|)|nng  and  pulverizing  in  the  winter. 

The  capacity  of  the  i)lant,  from  pit  to  storage,  is  three  5-car  trains 
])er  hour,  or  slightly  over  540  tons  ])er  8-hr.  day.  The  maximum 
capacity  of  the  storage  building  is  18,000  tons.  The  total  annual 
capacity  of  the  plant  when  operated  as  described  is  50,000  tons.  This 
could  be  increased  without  extra  equipment  by  two-shift  operation 
during  the  summer,  with  storage  of  pulverized  clay,  as  well  as  crushed 
clay,  at  the  beginning  of  winter. 

The  storage  and  pulverizing  plant  require  192  hp.,  distributed  as 
follows : 

Horsepower  of 
Unit  driving  motor 

21    by   42-in.   single-roll   crusher 40 

18-in.  conveyor,   366   ft.  long 20 

18-in.   reclaiming  conveyor,  265  ft.  long 15 

18-in.   cross  conveyor  to  mill  building,   172  ft.   long 15 

Bin    feeders    2 

Raymond   mill    60 

Raymond   mill   fan   40 

Total -- 192 

]\Iiscellaneous  electric  ])ower  used  on  the  property  include  a  com- 
))ressor  for  oi)erating  rock  drills,  a  inimji  for  draining  the  pit,  and  a 
lighting  system.  ^ 

Samples  :  At  the  time  the  pit  w^as  sampled,  on  August  13,  1925,  the 
cut  had  not  been  carried  to  the  bottom  of  the  bed  that  corresponds  to 
the  No.  1-6  clay  (sample  No.  146,  p.  303)  on  the  pit  of  the  Lincoln 
Clay  Products  Co.  Two  samples  were  taken,  however,  both  of  which 
overlie  the  No.  1-6  clay.  In  1926,  a  sample  of  prepared  clay  was 
obtained  from  the  company,  and  was  tested  under  No.  280. 

No.  152  is  a  plastic  clay  lying  in  a  6-ft.  bed  beneath  the  capping. 
The  test  results  are  given  on  i)age  304.  No.  153  (p.  299)  is  a  less 
]ilastic  clay  from  a  3  to  4  ft.  bed  underlying  No.  152.  It  is  one  of  the 
clays  included  in  the  No.  0  (sample  No.  145,  p.  291)  clay  of  the  Lincoln 
Clay  Products  Co.  No.  280  is  more  re|)resentative  of  the  material 
available  during  the  normal  operation  of  the  pit.     (See  page  305.) 

GJaddhui,  McBran  and  Company.  Lincoln  Plant.  Athnll  McP>ean, 
president;  A.  L.  Gladding,  vice  president.    General  offices,  660  Market 


152 


DIVISION  OP  MINES  AND  MINING 


Street,  San  Francisco.  Chas.  Gladdino-,  manager  at  Lincoln.  The 
Lincoln  ])lant  of  Gladding',  McBean  &  Co.  was  established  in  1875,  and 
has  operated  continuously  since  that  time.  The  compa):y  was  incor- 
porated in  1886,  and  has  steadily  expanded  the  scope  oi  its  operations 
until  at  the  present  time  it  is  the  largest  clay  products  manufacturing 
organization  west  of  the  Mississipi)i  Valley.  The  company  now  owns 
three  large  plants,  one  at  Lincoln,  one  at  Glendale,  Los  Angeles  County, 
and  the  third  at  Auburn,  Washington.  It  has  recently  acquired  control 
of  the  Los  Angeles  Pressed  Brick  Co.,  operating  several  large  plants  in 
southern  California,  and  of  the  Denny-Renton  Clay  and  Coal  Co.  of 
Seattle,  Washington,  operating  two  plants  in  Washington  and  one  at 
Portland,  Oregon. 

The  Lincoln  plant  specializes  on  architectural  terra  cotta,  fire  brick, 
face  brick,  roofing  tile,  sewer  pipe,  chimney  pipe,  and  garden  pottery. 
A  fine  example  of  the  use  of  architectural  terra  cotta  manufactured  at 


Photo  No.  33.     Clay  pit  of  Gladding,  McBean  &  Co.,  at  Lincoln,  Placer  County. 

Lincoln  is  the  new  Russ  Building  in  San  Francisco.  Photo  No.  1 
(frontispiece)  is  a  view  of  this  building.  Many  other  important 
buildings  on  the  Pacific  Coast  have  been  faced  with  terra  cotta  from 
one  of  the  company's  plants. 

Clay  Deposit:  The  company  owns  480  acres  of  clay  land  in  Sec.  9 
and  10  of  T.  12  N.,  R.  6  E.,  M.  D.  M.  The  present  working  pit,  shown 
in  photo  No.  33,  is  in  the  SE]-  of  Sec.  9.  A  section  through  the  pit  is 
as  follows : 


Section  Through  Pit  of  Gladding,  McBean  &  Co.,  at  Lincoln. 

Sample     Test  data  Thicknes.s, 

No.           on  page                  Character  of  material  feet 

Lava:  Andesite-agglomerale    S 

155  325           Pit  sand  :   Iron-stained  clay,  sand  and  fine  gravel 10 

Sand  and  gravel,  not  usd 15 

156  299  Fire-proofing  clay,  corresponding  in  quality  and  thick- 

ness to  L.  C.  P.  Co.,  No.  0,  sample  No.  145 7 

157  304  Terra  cotta  clay,   corresponding  in   quality  and   thick- 

ness to  L.  C.  P.  Co.,  No.  1-G,  sample  No.  146 15 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  153 

Data  Avere  not  availablo  for  definitely  determining  the  correlation 
with  the  clay  beds  exposed  on  the  properties  to  the  north,  but  it  seems 
])robable  that  the  fire-proofingr  clay,  sample  No.  156,  corresponds  to  the 
No.  0  clay  of  the  Lincoln  Clay  Products  Co.,  sample  No.  145,  and  that 
the  terra  cotta  clay,  sample  No.  157,  corresponds  to  the  No.  1-6  clay, 
sample  No.  146.  The  overlyinj?  sand  and  j>ravel  beds  in  the  Gladdinj;, 
IMcBean  pit  would  indicate  that  the  lava  cap  was  laid  down  on  this 
area  before  these  beds  were  eroded,  whereas  to  the  north  most  of  the 
material  overlyinji-  the  clay  beds  had  been  removed  before  the  deposition 
of  lava,  and  in  some  places  the  ujiper  clay  beds  themselves  had  been 
partly  encroached  upon  by  erosion.  However,  the  bed  underlying  the 
terra  cotta  clay  is  of  similar  material,  which  indicates  either  that  the 
No.  7  and  No.  8  clays  of  the  Lincoln  Clay  Products  Co.  are  absent  here, 
or  that  the  correlation  does  not  hold. 

I\IiNiNG :  The  clay  is  mined  by  steam  shovel  in  benches,  as  shown  on 
photo  No.  33.  The  pit  is  over  1100  ft.  long:.  Waste  is  carried  to  the 
dump,  and  clay  to  the  plant,  on  an  industrial  railroad,  with  a  steam 
locomotive  and  5-ton  dump  cars.  The  production  of  clay  is  at  the  rate 
of  approximately  500  tons  per  day  during  the  dry  season.  Water  that 
runs  into  the  pit  during  the  winter  is  pumped  out  at  the  beginning  of 
each  dry  season,  and  little  pumping  is  ordinarily  required  during  the 
summer. 

Plant:  The  plant  occupies  a  25-acre  tract,  on  the  northern  edge  of 
the  town  of  Lincoln,  and  nearly  one  mile  southeast  of  the  clay  pit.  An 
airplane  view  of  the  ])lant  is  shown  on  photo  No.  34.  In  addition  to 
clays  from  the  local  pit,  clay  and  sand  from  lone,  clay  from  Natoma, 
quartz  from  various  sources,  and  grog  are  used  in  the  body  mixtures. 
In  the  design  and  operation  of  the  plant,  extreme  care  is  used  to  ensure 
uniformit}^  of  raw  materials,  and  accuracy  of  body  proportioning. 
I'pon  being  delivered  to  the  plant,  all  materials  are  stock-piled  sepa- 
rately in  a  covered  shed.  A  4-tou  traveling  crane  reclaims  the  mate- 
rials and  delivers  them  to  one  of  nine  small  bins,  which  feed  four  dry 
pans,  o])erated  to  grind  through  a  14-mesh  screen.  The  ground  mate- 
rials, still  se])arate,  are  then  elevated  to  storage  bins.  The  body  mix- 
tures are  proportioned  from  these  bins  by  means  of  disc  feeders. 

The  terra  cotta  body  mixture  contains  approximately  50%  terra 
cotta  clay,  10.0%  non-plastic  clay,  and  40.0%  grog,  by  volume  of  minus 
14-mesh  material.^ 

The  body  mixture  is  prepared  by  double  pugging,  and  the  average 
water  content  of  the  wads  is  26%.  The  wads  are  aged  under  damp 
burlap  in  cool  rooms  before  being  sent  to  the  pressers,  but  the  minimum 
aiding  period  is  often  only  two  or  three  hours.  The  pressing  room  has 
no  unusual  features.  All  of  the  terra  cotta  and  garden  pottery  are 
shaped  by  hand  pressing  in  plaster  molds. 

Terra  cotta,  roofing  tile  and  electrical  conduit  are  dried  in  Carrier 
ejector  humidity  driers,  which  are  designed  to  give  accurate  control 
over  the  four  factors  of  time,  temperature,  humidity  and  velocity  during 
drying.  Tlie  drying  cycle  in  use  at  the  time  of  visit  on  August  14, 
1925,  was  as  folloAvs:  The  drying  atmosphere  began  with  five  hours  at 
]20°  F.  and  60%  humidity  was  increased  by  steps  to  212°  and  50% 

'  Larkln.  P.  G.,  and  Curry,  E.  R.,  Notes  on  Terra  Cotta  Body  Shrinkage,  Jour.  Am. 
Cer.  Soc.  Vol.  8,  p.  113,  1925. 


154 


DIVISION  OP  MINES  AND  MINING 


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CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  155 

humidity,  in  a  period  of  five  hours,  tlien  Avas  held  at  212°  F.  Avith 
urailually  decreasing;  humidity  for  12  hours,  and  the  ware  was  finally 
drawn  about  one  hour  later.  The  averagre  dryinjr  cycle  thus  occupied 
23  hours.  Waste-heat  tunnel  driers  are  u.sed  for  firebrick  and  face 
brick. 

Eleven  down-draft  oil-fired  muff}e  kilns  are  in  use  for  terra  cotta 
firing.  The  body  and  glaze  mature  together  at  cone  4  (2000°  P.),  with 
a  heating  schedule  of  nearly  four  days.  Four  days  are  allowed  for 
cooling,  and  three  days  for  unloading  and  setting  for  the  next  burn, 
making  the  turn-over  time  11  days.  The  average  total  linear  shrinkage, 
on  a  plastic  basis,  is  6.9%.     The  body  color  is  buff. 

Fire  brick  are  made  from  a  mixture  of  terra  cotta  clay  (sample  No. 
157),  ground  fire  brick  grog,  and  fpiartz.  The  brick  are  shaped  in  a 
side-cut  auger-machine.  Three  round  down-draft  kilns  are  usually  in 
use  for  firing  fire  brick.  The  firing  cycle  occu])ies  five  to  six  days 
firing,  and  about  an  equal  time  cooling.  The  finishing  temperature 
corresponds  to  cone  11  down,  or  1285°  C. 

Face  brick  are  made  from  local  materials,  using  all  three  of  tlie 
materials  mined  in  the  company's  pit,  proportioned  according  to  colors 
desired.  Practically  all  the  face  brick  produced  in  the  ])lant  is  buff 
or  cream  color.  An  angei-  machine  shapes  the  brick,  which  are  either 
end-  or  side-cut.  They  are  fired  to  2200"  F.  in  round  down-draft  kilns, 
four  of  which  are  usually  in  use  for  this  class  of  ware. 

The  sewer  ])i])e  mixture  contains  'fire-proofing  clay'  (sample  No. 
156),  Tone  sand  and  grog.  Electrical  conduit  is  made  from  the  same 
mixture,  with  the  addition  of  some  Natonia  clay  (samjjje  No.  212,  j).  337).  ^'P 
Twelve  round  doAvn-draft  kilns  are  in  service  on  these  two  classes  of  %^ 
ware,  firing  to  a  maximum  tem]ierature  of  1200"  C.  in  about  seven 
days,  including  the  salt  glazing  period,  then  cooling  for  a  nearly  equal 
period. 

Roofing  tile  is  made  from  a  mixture  of  local  materials  and  Natoma 
clay.  Drain  tile  is  made  from  a  similar  mixture.  Both  are  shaped  on 
an  auger  machine.  The  roofing  tile  is  fired  in  a  tunnel  kiln,  363  feet 
long,  with  a  43  hour  cycle  to  a  maximum  temperature  of  cone  3 
(1145°  F.).  Studies  made  at  the  plant  liave  demonstrated  a  saving  of 
50%  of  the  fuel  consumption  of  a  round  down-draft  kiln  for  this  class 
of  ware. 

In  addition  to  the  products  already  mentioned,  flue  lining  is  manu- 
factured. Four  round  down-draft  kilns  are  in  use  for  firing  this 
product. 

All  the  firing  is  done  with  oil  fuel,  atomized  by  compressed  air.  A 
complete  pyrometric  control  of  all  kilns  ensures  uniform  firing  condi- 
tions, and  economy  of  fuel.  Electric  i)Ower  is  used  throughout  the 
plant. 

The  plant  contains  an  architectural  and  sculpturing  dej)artment.  a 
drafting  department,  and  a  ceramic  laboratory.  As  in  most  plants 
specializing  in  architectural  terra  cotta,  the  staff  of  the  ceramic  labora- 
tory spend  the  greater  i)art  of  their  time  developing  glazes. 

About  600  men  are  emi)loyed  in  the  plant,  of  Avhom  a  large  proportion 
are  on  ])iece  work.  A  summary  of  the  kiln  equi])ment  and  the  ap])roxi- 
mate  annual  ca])acity  of  various  classes  of  ware  are  given  in  the  follow- 
ing table : 


/. 


156 


DIVISION  OF  MINES  AND  MINING 


Kiln  Data  and  Approximate  Annual  Capacity  of  Gladding,  McBean  &  Co.  Plant 

at    Lincoln. 

Firing' 

No.  of             Type  of       Max.  temp.,  time,  Annual 

Class  of  ware                      kilns                  kiln                   °F.  days  capacity 

Arcliitectural  terra  cotta-          11               Muffle  d.d.             2000  3.75  12,000  tons 

Sewer  pipe  and  conduit 12               Round  d.d.            2190  7  20,000  tons 

Face  brick 4              Round  d.d.             2190  6  3,200  M 

Firebrick    2               Round  d.d.             2370  6  1,600  M 

Chimney  pipe 4              Round  d.d.             1830  4  3,000  tons 

Drain  tile Set  with  other  ware 

Roofing  tile 1               363  ft.  tunnel        1975  43  hrs.  12,000  tons 

Garden  pottery Occasional 

Lincoln  Clay  Products  Co.  M.  J.  Dillman,  president,  Lincoln.  The 
Lincoln  Clay  Products  Company  has  no  manufacturing  plant,  and  is 
exclusively  engaged  in  the  mining  of  clays. ^  The  property  is  located  two 
miles  northwest  of  Lincoln,  in  "the  N|  of  Sec.  4,  T.  12  N.,  R.  6  E., 
M.  D.  M.     It  has  been  in  operation  for  over  thirty  years. 


Photo  No.  35.  General  view  of  the  pit  and  plant  of  the  Lincoln  Clay  Products 
Co.,  looking  south  from  the  top  of  the  storage  building  of  the  Clay  Corpora- 
tion of  California.  The  Clay  Corporation's  offlce  building  is  in  the  right 
foreground. 


The  pit  is  w^orked  in  benches  by  a  combination  of  a  spiral  a])proacli 
and  an  incline  as  shown  in  photos  Nos.  35,  36  and  37.  Benches  are 
established  on  the  bottom  of  each  clay  bed,  or  series  of  beds,  that  is  to 
be  mined  separately.  Gasoline  locomotives  are  used  to  haul  train- 
loads  of  stripping  or  clay  from  the  upper  beds  and  an  incline  hoist  is 
used  to  remove  the  clay  that  is  mined  near  the  bottom  of  the  pit.  The 
pit  is  over  1200  feet  long  and  600  feet  wide  and  the  maximum  depth  is 
60  feet. 

The  clay  is  loosened  by  hand  di'illing  and  blasting.  A  IJ  cu.  yd. 
gasoline  shovel  is  used  for  loading  clay  from  tlie  thicker  beds,  and  hand 
loading  is  used  on  the  thinner  beds.  Five  gasoline  locomotives  are  in 
service.     Two  of  these  weigh  three  tons  and  the  others  weigh  four,  six, 

'  A  clay-working  plant  i.s  contemplated   in  the  near  future. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


157 


Photo  No.   36.     Eastern  end  of  pit  of  Lincoln  Clay  Products  Co.,  near  Lincoln. 
Samples  No.  145  to  150  were  taken  from  the  pit. 


Photo  No.  37.  Western  end  of  pit  of  Lincoln  Clay  Products  Co.  with  clay 
grinding  and  storage  plant  of  the  Clay  Corporation  of  California  in  the 
middle  background. 


158  DIVISION  OF  MINES  AND  MINING 

and  eip:ht  tons,  respectively.     A  eentrifn^al  ])um])  is  used  to  remove 
run-otf  water  from  the  pit. 

A  section  tlirougli  the  pit  follows : 

Average 
Sample     Test  data  thicknes.s, 

No.  on  page  Class  of  material  feet 

Soil  and  gravel 1-  3 

Lava    1-  6 

145  291  -Xo.      0  clay:   Face  brick  body 8 

146  303  No.      1-6   clay:   Terra   cotta   body 1  .o 

147  303  No.      7   clay  :   Tile,  face  brick,  sewer  pipe.     High  in  iron.  12 

148  336  No.      8  clay:   Higher  in  iron  than  No.  7 6 

149  298  No.      9  clav :   Similar  to  No.   1-6 8 

150  291  No.   10  clay:   Similar  to  No.  9 22 

A  larjre  storage  shed,  shoAvn  in  photo  No.  35,  provides  storage  of 
clay  during  the  rainy  season,  allows  for  fluctuations  in  mining  and 
shipping  during  the  season,  ensures  a  certain  degree  of  mixing  to  mini- 
mize the  effect  of  local  variations  in  the  quality  of  clay,  and  permits 
seasoning  of  clay  for  those  customers  who  so  desire. 

In  the  fall  of  1918  a  washing  plant  was  built  for  the  purpose  of 
investigating  the  commercial  pos.sibilities  of  marketing  a  waslied 
product.  The  clay  was  ground  in  a  Graupner  centrifugal  mill,  mixed 
with  water,  and  settled  in  vats.  The  thickened  slip  was  dipi)ed  out  by 
hand  and  sun-dried  in  shallow  trays.  The  principal  effect  of  tliis 
process  was  to  eliminate  a  certain  proportion  of  the  sand  that  is  present 
in  the  raw  clay,  thereby  producing  a  finer  grained  clay  that  has  a  more 
uniform,  but  greater,  shrinkage.  On  account  of  high  freight  rates  on 
washed  clay,  compared  to  crude  clay,  and  because  of  the  fact  that  the 
washed  clay  did  not  ]iossess  sufficient  advantages  in  use,  washing  was 
discontinued  after  a  brief  period.  In  order  to  permit  a  study  of  the 
properties  of  the  washed  material,  ]\Ir.  Dillman  kindly  gave  tlie  writer 
a  sack  from  the  warehouse.  This  is  sample  No.  151,  and  the  test 
results  are  given  on  page  303. 

An  average  of  12  men  are  employed.  The  annual  output  varies  with 
market  demands,  but  is  usually  in  excess  of  50,000  tons.  The  selling 
price  of  the  clay,  f.  o.  b.  cars  at  the  plant,  averages  $1.75  per  ton. 

Miscellaneous  Deposits. 

Previous  publications^  by  the  State  Mining  Bureau  have  reported 
occurrences  of  clay  at  various  points  along  or  near  the  line  of  the 
Southern  Pacific  Railroad,  from  Alta  to  Gorge.  The  most  i)romising 
of  these  were  visited  in  August,  1925,  and  were  in  each  case  found  to 
be  derivatives  of  the  andesitic  tuff-breccias,  rhyolite  tuffs,  or  volcanic 
ashes  that  are  remnants  of  the  great  Tertiary  volcanic  deposits  that  at 
one  time  completely  covered  the  basement  rocks  of  tlie  west  slope  of 
Sierra  Nevad?  Mountains,  before  the  more  recent  period  of  tilting  and 
stream  cutting  that  has  resulted  in  the  ])resent  topography.  Rock 
decomposition  and  alteration  has  i)rogre.ssed  to  a  varying  degree  in 
many  of  these  materials,  with  the  result  that  in  places  there  are  exten- 
sive beds  of  fine-grained,  white,  greenish-white,  or  yellowish-white 
material  having  a  certain  degree  of  plasticity  that  are  often  mi.staken 
for  useful  clays.  They  are,  however,  of  no  value  for  ceramic  ])urposes, 
on  account  of  high  drying  and  firing  shrinkage,  low  cohesion  in  the 
partly-dried  condition  which  results  in  serious  cracking  during  drying, 

»  Prel.  Rept.  No.  7,  p.  67-73. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  159 

low  fusibility,  and  dii'ty  yollnw  or  red  firiii<i-  colors.  Even  if  tlioy  can 
be  successfully  dried  without  crackiui:-,  the  excessive  sliriukajre  will 
cause  warping-,  aiul  they  are  i)ractically  impossible  to  fire  without 
splitting.  A  characteristic  feature  tliat  renders  easy  the  field  elimina- 
tion of  such  materials  is  the  spongy,  sticky  plasticity  developed  upon 
the  addition  of  water,  coujjled  witli  the  large  amount  of  water  that  the 
material  will  absorb  to  (Un-elop  this  'plasticity,'  usually  amounting  to 
over  75%  of  the  solids  by  weight. 

As  representative  of  this  class  of  material,  samjdes  No.  161  to  165, 
inclusive,  were  taken,  and  two  of  them,  No.  IGl  and  163,  were  submitted 
to  a  portion  of  the  ceramic  tests. 

Sample  No.  161  was  taken  from  a  50-foot  railroad  cut,  1  mile  west 
of  Gorge,  between  mile  157  and  158  on  the  railroad.  The  bed  sami)led 
was  6  to  8  feet  thick,  and  is  exposed  for  a  length  of  over  300  feet  in  the 
cut.  It  is  overlain  by  12  feet  (maximum)  of  overburden  on  the  south 
side  of  the  cut,  consisting  of  gravel  and  decomposed  andesite,  and  is 
underlain  by  white  rhyolitic  tuff  (?).  The  sample  developed  sticky 
plasticity  with  71. 5/t  water,  and  with  less  water  was  merely  spongy 
Avithout  much  cohesion.  The  test  pieces  all  sjilit  badly  during  drying, 
and  while  hard,  were  very  brittle.  The  calculated  linear  drying 
shrinkage,  based  on  dry  length,  was  28.5%.  It  was  not  possible  to 
obtain  the  dry  transverse  strength  of  the  undiluted  material,  and  the 
test  pieces  were  not  fired. 

Samples  No.  162,  163,  and  164  were  taken  from  successive  beds  (top 
to  bottom)  of  material  exi)osed  along  the  highway  0.9  mile  above 
Baxter,  or  2.1  miles  above  Towle.  Each  bed  is  approximately  2.5  feet 
thick,  and  the  series  is  exposed  for  a  distance  of  over  100  feet.  It  is 
overlain  by  from  0  to  3  feet  of  white  sand  tuff.  Some  tests  were  made 
on  No.  163,  but  tlie  others  were  discarded.  The  plastic  working  prop- 
erties of  sample  No.  163  are  similar  to  those  possessed  by  sample  No.  161, 
except  that  the  presence  of  a  larger  amount  of  non-plastic  material 
soriiewhat  modifies  the  stickiness.  The  water  of  plasticity  is  67.1%, 
the  calculated  linear  shrinkage,  dry  basis,  is  18.4%  and  the  total  drying 
and  firing  slirinkage  to  cone  06  (1005°  C.)  is  22.1  per  cent  of  the  plastic 
length.  Visible  drying  cracks  did  not  develoji,  but  the  erratic  results 
obtained  from  dry  transverse  strength  tests  indicates  the  presence  of 
lines  of  weakness.  All  of  the  fired  pieces  cracked  badly.    (See  page  350.) 

Sample  No.  165  was  from  a  railroad  cut  1100  feet  above  (east)  of 
Alta  station,  described  ami  illustrated  in  Preliminary  Report  No.  7, 
l)age  73.  The  exposed  face  is  35  feet  thick  and  600  feet  long,  con- 
sisting of  alternating  layers  of  fine  grained  yellowish  i)lastic  'clay,' 
and  of  a  sandier  and  whiter  variety  of  the  same  material,  overlain  by 
red  decomposed  andesite  varying  from  two  to  eight  feet  in  thickness. 
The  portion  sampled  was  from  a  yellowish  plastic  bed  varying  from 
four  to  ten  feet  in  thickness,  midway  between  the  top  and  bottom  of 
the  exposure.  No  tests  were  made  other  than  pugging  a  small  portion 
of  the  material  with  water  and  noting  its  general  similarity  to  the 
materials  represented  by  samples  No.  161-164. 

Valleij  View  Mine.  Owned  by  Judge  J.  B.  Landis  and  Ed.  Gavlord, 
of  Auburn.  Tliis  property  is  in  SE^  Sec.  12  and  NEj  Sec.  24,  T. 
13  N.,  R.  6  E.,  M.  D.  ]M.,  eight  miles  by  road  northeast  of  Lincoln. 


160 


DIVISION  OF  MINES  AND  MINING 


Under  tlio  name  of  Wliiskoy  Hill  or  IIar])ondino;  Mine,  it  was  Avorked 
for  «>'old  in  the  sixties,  but  later  developeil  into  a  eojjper  pi-operty.  In 
the  lower  workingis,  sphalerite  and  pyrite  increased  in  quantity  and  the 


Photo    No.    38.     Valley    View    Mine,    Placer    County.      Portal    of    lower    tunnel. 
(Sample  No.  261  from  glory  hole  that  connects  with  the  tunnel.) 


Photo  No.    39.     Valley  View  Mine,   Placer  County.     Upper   workings.      (Sample 
No.  262  from  bank  to  left  (east)  of  center  of  view.) 

copper  minerals  decreased.  There  has  been  no  production  since  1918. 
The  ore  occurs  in  part  in  altered  dikes  which  intrude  the  amphibolite 
schist  country  rock.  In  the  upper  workings,  still  accessible  through  a 
tunnel,  a  glory  hole,  and  an  open  cut,  the  dike  rock  has  been  kaolinized. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  161 

The  degree  of  kaoliiii/fitioii  and  tlie  percentage  of  iron  vary  eonsid- 
eral)ly  in  different  i)arts  oi'  tlie  exposures,  but  in  places  the  material  is 
well  kaolinized,  lias  fair  plasticity,  and  is  comparatively  free  from  iron. 
Photos  No.  .'58  and  8i)  are  views  of  the  property.  Three  samples  were 
taken.  No.  2(il  (p.  o2S)  was  taken  from  an  undci-ground  cliamber  that 
connects  by  a  chute  to  the  tunnel,  the  i)ortai  of  which  is  shown  on  photo 
No.  38.  The  sample  represents  a  small  kidney  of  kaolinized  material, 
exposed  over  an  area  about  10  feet  square,  and  at  least  4  feet  thick. 
A  ])eculiarity  of  the  sample  is  that  while  it  is  distinctly  red-burning, 
it  has  a  softening  point  of  cone  28  (1615°  C).  No.  262  (p.  350)  was 
taken  from  the  open  cut  shown  in  photo  No.  39,  and  is  representative  of 
the  material  from  the  bank  to  the  left  (east)  of  the  center  of  view. 
Tliis  material  has  little  or  no  ceramic  value.  No.  263  (p.  292)  is  a 
sample  of  white  kaolin  from  the  same  open  cut.  It  occurs  as  small 
isolated  pockets,  some  of  which  are  clearly  shown  on  the  right-hand 
side  of  photo  No  39  as  white  patches.  The  material  is  nearly  wiiite- 
burning.  has  fair  pla.sticity,  and  a  high  softening  temperature  (cone 
32-33,  about  1720°  C).  Unfortunately,  thei'e  is  little  indiccition  that 
large  bodies  of  equally  good  material  will  be  found  on  the  property. 

Bibl  (Vallev  View  Mine)  :  Cal.  State  Min.  Bur.  Bull.  50,  p.  174. 
Kept.  XV,  pp.  327-330;  XXIII,  pp.  246-247  and  286. 

RIVERSIDE    COUNTY. 
General    Features. 

Riverside  County  lies  in  the  southern  portion  of  the  state.  It  is 
bounded  on  the  north  by  San  Bernardino  County,  on  the  east  by  the 
state  of  Arizona,  on  the  south  by  Imperial  and  San  Diego  counties,  and 
on  the  west  by  Orange  County.  The  county  has  an  area  of  7420  square 
miles  and  a  population  of  60,297  (1920  census).  It  is  the  fourth 
county  in  size  and  the  seventh  in  regard  to  the  total  value  of  mineral 
output  (1925). 

The  surface  of  Kiverside  County,  like  that  of  much  of  southeastern 
California,  is  characterized  by  bare  mountain  ranges,  separated  by 
nearly-level  arid  belts  of  varying  width.  The  minor  ranges  of  moun- 
tains rise  abruptly  from  the  desert  plains,  having  the  appearance  of 
being  the  summits  of  larger  ranges  whose  bases  are  buried  beneath  the 
loose  deposits  of  the  desert.  The  San  Bernardino  and  San  Jacinto 
mountains  are  the  most  prominent  ranges,  the  peaks  of  which  rise  to 
more  than  10,000  feet  above  sea  level.  On  the  western  edge  of  the 
county,  and  sei)arating  it  from  Orange  County,  is  the  Santa  Ana  Range. 

Geology. 

A  detailed  study  of  the  geology  of  Riverside  County  has  not  yet  been 
made.  In  the  desert  areas  of  the  eastern  portion  of  the  county,  the 
principal  formations,  besides  Quaternary  gravels,  are  pre-Cambrian 
and  Paleozoic  metamorphics ;  some  Tertiary  sediments,  mostly  Pliocene ; 
and  various  plutonic  and  volcanic  rocks.  In  the  western  portion  of  the 
county,  near  Orange  County,  are  extensive  areas  of  Triassic,  Upper 
Cretaceous,  Eocene  and  Miocene  age.^ 

» Smith,  J.  p.,  The  geologic  formations  of  California :  State  Min.  Bur.  Bull. 
72  and  Geological  Map.     See  also  for  bibliography  ui-  to  date  of  issue  in  1916. 

11 — 54979 


162  DIVISION  OF  MINES  AND  MINING 

The  mineral  resources  of  the  county  incIivJo  V^rick,  cement,  clay,  coal, 
copper,  feldspar,  gems,  gold,  gypsum,  iron,  lead,  limestone,  manganese, 
magnesite,  marble,  mineral  paint,  mineral  water,  salt,  soapstone,  silver, 
miscellaneous  stone,  and  tin.  In  11)25,  seventeen  dift'erent  minerals 
were  commercially  produced,  the  most  important  being,  in  the  order 
of  their  production,  cement,  miscellaneous  stone,  brick  and  hollow 
building  tile,  pottery  clay,  silica  (quartz),  granite,  feldspar,  and  lead. 

Clay    Resources. 

The  Alberhill-Corona  district  in  western  Riverside  County  is  one  of 
the  three  most  important  clay  producing  areas  in  the  state.  The  clay 
deposits  extend  in  a  belt  along  the  Temescal  Valley  for  fifteen  miles 
from  Elsinore  on  the  southeast  to  Corona  on  the  northwest.  The  clays 
were  laid  down  in  Eocene  time,  when  the  Temescal  Valley  was  an  arm 
of  the  sea  opening  northward  into  the  valley  of  western  San  Bernardino 
County  and  extending  southerly  to  Temecula.  The  width  of  the  basin 
is  from  one  to  two  miles,  and  the  depth  in  places  is  over  600  feet.  A 
property  map  of  the  district  is  given  on  plate  X. 

The  general  character  of  the  deposits  is  well  described  in  the  follow- 
ing excerpts  from  an  article  by  the  late  J.  H.  Hill,^  then  president  of 
the  Alberhill  Coal  and  Clay  Company,  the  largest  producer  in  the 
district : 

"At  the  Alberhill  pits,  the  clays  present  a  wide  diversity  of  color,  character,  and 
degree  of  consolidation.  An  extraordinary  variety  is  found,  including  siliceous  fire- 
clays, ball  clays,  plastic  white-  and  buff-ljurning  clays,  highly  aluminous  and  very 
refractory  clays,  numerous  red-burning  clays,  and  an  extensive  bed  of  material  from 
which  a  china  clay  is  obtained  by  v^ashing.  A  bed  of  lignite  coal  ranging  from  two 
to  eleven  feet  in  thickness  occurs  conformably  with  the  clay  strata,  and  adjacent  to 
this  the  best  fireclays  are  found.  The  strata  are  regular  and  persistent,  and  dip  to 
the  southwest  with  an  average  value  of  10  degrees,  with  local  variations  due  to  an 
undulatory  or  wavy  folding. 

"Minor  local  disturbances  appear  to  have  prevailed  at  Intervals  during  deposition 
of  these  clays,  and  coarse  sandy  beds  are  interspersed  with  fine-grained  plastic  clays. 
In  these  sandy  beds,  the  coarse  silica  sand  is  often  intermixed  in  a  sporadic  and 
irregular  fa.shion  with  the  accompanying  clay  substance.  Mottled  clays  apparently 
due  to  simultaneous  deposition  of  different  kinds  of  sediments  derived  from  separate 
sources  are  also  found.  The  beds  in  general  seem  to  indicate  that  long  quiescent 
periods  during  which  fine-grained  clays  were  laid  down  were  preceded  and  followed 
by  stormy  periods  when  frequent  freshets  or  strong  tidal  currents  brought  in  coarse 
silica  sand  and  granite  debris  from  surrounding  highlands.  The  top  soils  of  the 
region  consist  of  debris  of  disintegrated  granite,  and  vary  from,  a  few  inches  to 
many   feet    in   thickness. 

"Owing  to  the  masking  of  the  surface  by  the  layer  of  disintegrated  granite 
material,  the  total  extent  of  the  Alberhill  deposit  has  not  yet  been  fully  determined. 
However,  a  large  number  of  bore  holes  have  been  put  down  on  widely  separated 
portions  of  the  property,  and  in  every  case  clays  of  good  quality  were  found  to  the 
full  extent  of  the  hole  in  depth.  From  this  and  other  evidence,  it  seems  quite 
probable  that  the  entire  mass  of  the  small  moimtain.  above  the  valley  floor  and  for 
an  unknown  depth,  is  clay.  A  few  isolated  occurrences  of  shale  have  been  noted. 
Exploration  to  date  has  been  sufficient  to  indicate  beyond  doubt  that  the  quantity  of 
readily  available  clay  is  so  vast  as  to  be  inexhaustible  for  all  practical  purposes. 
*  *  *  The  hill  comprising  the  deposit  is  about  two  and  one-quarter  miles  long  and 
one  mile  in  width,  with  an  average  elevation  of  16S0  feet.  The  main  line  tracks  of 
the  railway  *  •  *  are  at  an  elevation  of  1277  feet.  *  *  *  The  present  pits 
are  all  somewhat  above  the  level  of  the  railroad  tracks." 

While  Mr.  Hill's  estimate  of  clay  reserves  may  have  been  somewhat 
optimistic,  in  the  light  of  more  recent  work  which  indicates  that  the 
deposits  lie  in  the  form  of  a  synclinal  trough  again.st  the  eroded  surface 
of  the  mountain  ranges  on  each  side  of  the  valley,  it  is  substantially 
true  that  the  supply  of  readily  available  clay  is  sufficient  to  last  for 
many  years,  even  at  increased  rates  of  production.  Considering  the 
district  as  a  whole,  the  principal  deposits  lie  on  the  eastern  side  of  the 

*  Clay  deposits  of  the  Alberhill  Coal  and  Clay  Company :  State  Mineralogist's 
Report  XIX.  pp.  185-210,  1923. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


163 


[it  deposits  in  the  floor  of  the  vallev  and  toward  the  western 

"     '      *       '^  "■         '•     "•-   and 

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to  work  the  coal  beds  that  occur  here,  and  for  13  years  previous  to 
1895  the  property  was  developed  solely  as  a  coal  mine.     The  production 


162  DIVISION  OF  MINES  AND  MINING 

The  mineral  resources  of  the  county  inelu'Je  V^rick,  cement,  clay,  coal, 
copper,  feldspar,  gems,  gold,  gypsum,  iron,  lead,  limestone,  manganese, 
magnesite,  marble,  mineral  paint,  mineral  water,  salt,  .s()ai)stone,  silver, 
miscellaneous  stone,  and  tin.  In  l!)2o,  seventeen  ditferent  minerals 
were  commercially  produced,  the  most  important  being,  in  the  order 
of  their  production,  cement,  miscellaneous  stone,  brick  and  hollow 
building  tile,  pottery  clay,  silica  (quartz),  granite,  feldspar,  and  lead. 

Clay    Resources. 

The  Alberhill-Corona  district  in  western  Riverside  County  is  one  of 
the  three  most  important  cla}^  producing  areas  in  the  state.  The  clay 
deposits  extend  in  a  belt  along  the  Temescal  Valley  for  fifteen  miles 
from  Elsinore  on  the  southea.st  to  Corona  on  the  northwest.  The  clays 
were  laid  down  in  Eocene  time,  when  the  Temescal  Valley  was  an  arm 
of  the  sea  opening  northward  into  the  valley  of  western  San  Bernardino 
County  and  extending  southerly  to  Temecula.  The  width  of  the  basin 
is  from  one  to  two  miles,  and  the  depth  in  places  is  over  600  feet.  A 
property  map  of  the  district  is  given  on  plate  X. 

The  general  character  of  the  deposits  is  well  described  in  the  follow- 
ing exceri)ts  from  an  article  by  the  late  J.  H.  Hill,^  then  president  of 
the  Alberhill  Coal  and  Clay  Company,  the  largest  producer  in  the 
district : 

"At  the  Alberhill  pits,  the  clays  present  a  wide  diversity  of  color,  character,  and 
degree  of  consolidation.  An  extraordinary  variety  is  found,  including  siliceous  fire- 
clays, ball  clays,  plastic  white-  and  buff-burning  clays,  highly  aluminous  and  very 
refractory  clays,  numerous  red-burning  clays,  and  an  extensive  bed  of  material  from 
which  a  china  clay  is  obtained  by  washing.  A  bed  of  lignite  coal  ranging  from  two 
to  eleven  feet  in  thickness  occurs  conformably  with  the  clay  strata,  and  adjacent  to 
this  the  best  fireclays  are  found.  The  strata  are  regular  and  persistent,  and  dip  to 
the  southwest  with  an  average  value  of  10  degrees,  with  local  variations  due  to  an 
undulatory  or  wavy  folding. 

"Minor  local  disturbances  appear  to  have  prevailed  at  intervals  during  deposition 
of  these  clays,  and  coarse  sandy  beds  are  interspersed  with  fine-grained  plastic  clays. 
In  these  sandy  beds,  the  coarse  silica  sand  is  often  intermixed  in  a  sporadic  and 
irregular  fashion  with  the  accompanying  clay  substance.  Mottled  clays  apparently 
due  to  simultaneous  deposition  of  different  kinds  of  sediments  derived  from  separate 
sources  are  also  found.  The  beds  in  general  seem  to  indicate  that  long  quiescent 
periods  during  which  fine-grained  clays  were  laid  down  were  preceded  and  followed 
by  stormy  periods  when  frequent  freshets  or  strong  tidal  currents  brought  in  coarse 
silica  sand  and  granite  debris  from  surrounding  highlands.  The  top  soils  of  the 
region  consist  of  debris  of  disintegrated  granite,  and  vary  from  a  few  inches  to 
many  feet   in   thickness.  v 

"Owing  to  the  masking  of  the  surface  by  the  layer  of  disintegrated  granite 
material,  the  total  extent  of  the  Alberhill  deposit  has  not  yet  been  fully  determined. 
However,  a  large  number  of  bore  holes  have  been  put  down  on  widely  separated 
])ortions  of  the  property,  and  in  every  case  clays  of  good  quality  were  found  to  the 
full  extent  of  the  hole  in  depth.  From  this  and  other  evidence,  it  seems  quite 
probable  that  the  entire  mass  of  the  small  mountain,  above  the  valley  floor  and  for 
an  unknown  depth,  is  clay.  A  few  isolated  occurrences  of  shale  have  been  noted. 
Exploration  to  date  has  been  sufficient  to  indicate  beyond  doubt  that  the  quantity  of 
readily  available  clay  is  so  vast  as  to  be  inexhaustible  for  all  practical  purposes. 
•  *  *  The  hill  comprising  the  deposit  is  about  two  and  one-quarter  miles  long  and 
one  mile  in  width,  with  an  average  elevation  of  16S0  feet.  The  main  line  tracks  of 
the  railway  •  *  *  are  at  an  elevation  of  1277  feet.  *  *  *  xhe  present  pits 
are  all  somewhat  above  the  level  of  the  railroad  tracks." 

While  Mr.  Hill's  estimate  of  clay  reserves  may  have  been  somewhat 
optimistic,  in  the  light  of  more  recent  work  which  indicates  that  the 
deposits  lie  in  the  form  of  a  synclinal  trough  against  the  eroded  surface 
of  the  mountain  ranges  on  each  side  of  the  valley,  it  is  substantially 
true  that  the  supply  of  readily  available  clay  is  sufficient  to  last  for 
many  years,  even  at  increased  rates  of  production.  Considering  the 
district  as  a  whole,  the  principal  deposits  lie  on  the  eastern  side  of  the 

'  Clav  deposits  of  the  Alberhill  Coal  and  Clay  Company :  State  Mineralogist's 
Report  XIX,  pp.  185-210,  1923. 


ri.ATK  X,      JTupcily  riiiii]  uf  AUji.iliiil-Curiiiiu.  diatiiL-t.  Riverside  Ouiiily.      (By   courtesy   of  Uubt.    LiiUuii.) 


OV'J — facing  page  1C2 


162  DWISION  OP  MINES  AND  MINING 

The  mineral  resources  of  the  county  inclu'le  brick,  cement,  c 
copper,  feldsDar,  irems.  Qokl.  t>-vi)siini    imn    it.u,i    i;,.ioc.+r>.,.^   -^- 

magnesit 
miscellan 
were  con 
of  their 
building 

Clay    Resc 

The  A 

the  three 
deposits 
from  Els 
were  laid 
of  the  sec 
County  a 
is  from  c 
property 
The  ge 
ing  exeer 
the  Albe 
district : 

"At  the 
degree  of  ( 
clays,   ball 
refractory 
which  a  ch 
to  eleven  f. 
this  the  be 
the  southw 
undulatory 

"Minor  1 
of  these  elf 
In  these  sj 
irregular  f; 
due  to  simi 
sources  art 
periods  dur 
by  stormy 
silica  sand 
region  con; 
many  feet 

"Owing 
material,  tl 
However,  s 
portions  of 
full  extent 
probable  th 
an  unknow 
Exploratior 

readily  ava 
*      *      *      "J" 

one  mile  in 
the  railwaj 
are  all  som 

While  : 
optimistic 
deposits  1 
of  the  m( 
true  that 
many  yeg 
district  af 


'  Clay    deposits    of    the    Alberhill    Coal    and    Clay    Company :    State    Mineralogist's 
Report  XIX,  pp.  185-210,  1923. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


163 


valley,  but  (loi)osits  in  the  floor  of  the  valley  and  toward  the  western 
side  are  of  ini|)or1an('('  at  a  nninber  of  plaees.  Foidinji',  faultin^^,  and 
erratic  deposition  aic  most  proiionneed  on  tiie  eastei'n  side  of  the  valley 
ill  the  vicinity  of  Alhcrhili.  The  Emsco  de])osit,  on  the  same  side  of 
the  valley,  at  an  elevation  of  about  200  feet  above  the  Moor,  and  abont 
six  miles  to  the  nortlnve.st  of  All)erliill  (see  maj),  plate  X),  shows  little 
evidence  of  structural  complexity,  and  the  character  of  the  material 
ill  the  different  beds  is  uniform  over  a  lar.ue  area.  This  same  condition 
(u-evails  at  most  of  the  west  side  pits,  except  the  IMcKni^ht  jiit  (Pacific 
(May  Products  Company),  near  the  northern  limit  of  the  clay  belt, 
west  of  Corona,  where  the  structure  is  more  comi)lex. 

'Slant  of  the  pi'omisin^'  clay  land  in  the  district  has  been  purchased  or 
leased  by  various  companies.  The  ac(|uisition  of  ])roperty  has  been 
particularly  active  since  11)24.  when  it  became  apparent  that  a  railroad 
connection  was  to  be  made  from  Alberhill  to  Corona.     This  line  is  now 


6ectien  Pas.'fs 
In  Rear  Of  Mam  P»t 


Pit 
\ 


\ 

rautt 


R.4. 
Bone 

Htd. 
m»tH€ 


Lignite 
Coat 


Pink 

=  ~|m»ttK 


I'l.ATic  XI.      ]  )iaf;rammjiti(;  section  of  .strata  at  Alberhill,    in  a  general  west-east  line. 
(From  Slate  Mineralogist's  Report  XIX,   p.    1 90,   1923.) 


completed,  and  has  not  only  resulted  in  a  decrease  in  the  freight  rate 
from  Alberhill  to  Los  Angeles,  but  has  eliminated  long  truck  hauls 
throughout  the  district. 

Outside  of  the  Alberhill-Corona  district,  few  commercial  clay  deposits 
have  been  found  in  the  county.  Common  clays  are  sufficiently  abundant 
near  the  more  populous  i)arts  of  the  county  to  serve  all  re((uirements 
for  the  manufacture  of  common  brick.  The  desert  portions  of  the 
county  have  not  been  thoroughly  prospected  for  clays,  and  there  is  a 
chance  that  in  the  future  a  few  interesting  deposits  will  be  discovered. 

Alberhill  Coal  and  Clay  Company.  Chas.  Biddle,  general  manager, 
Alberhill,  California.  This  com])any  owns  nearly  2000  acres  of  prop- 
erty, parts  of  which  are  leased  to  other  companies.  The  principal 
holdings  are  shown  on  plate  X.  The  company  was  originally  organized 
to  work  the  coal  beds  that  occur  here,  and  for  13  years  previous  to 
1895  the  property  was  developed  solely  as  a  coal  mine.     The  production 


164 


DIVISION  OP  MINES  AND  MININO 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


165 


of  clay  started  in  1S95  and  it  has  been  continuous  since.  The  company 
lias  no  clay-working  plants,  but  sells  clays  to  many  manufacturers 
throughout  California,  particularly  in  the  Los  Angeles  district.  More 
than  thirty  varieties  of  clav  are  mined  and  marketed. 


Photo  No.   41.     Alberhill  Coal  &  Clay  Company.  Cut  connecting  main  and  west 
pits.       'Die   AlVierhill    plant   of   Gladding,    McBean    &   Company    (formerly 
Los  Angeles   Pressed   Brick   Company)    is   in   the   background.     Riverside 
County.      (From  State  Mineralogist's  Report  XIX,  p.  189,  1923.) 


Photo  No.    42.     Alberhill   Coal   &  Clay  Company.      One   of   the   loading  trestles. 
Riverside  County.     (From  State  Mineralogist's  Report  XIX,  p.  191,  1923.) 

The  operations  of  the  company  were  described  by  the  late  J.  H.  Hill 
in  an  earlier  report^  by  the  Bureau.  For  the  sake  of  completeness, 
this  article  is  freely  used  in  the  present  report,  with  some  additional 

'Hill,  J.  H.,  op.  cit. 


166 


DIVISION  OF  MINES  AND  MINING 


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CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


167 


Photo  No  44.  AlberhiU  Coal  &  Clay  Company.  Riverside  County. 
An  exposure  of  lignite  coal.  The  clay  stratum  directly  below 
the  coal  is  SH-4  (sample  No.  273)  ;  that  directly  above  is  SH-o 
(sample  No.  28).  (From  State  Mineralogist's  Report  XIX, 
p.  200,  1923.) 


168 


DIVISION  OP  MINES  AND  MINING 


details  on  recent  developments.     The  reader  is  referred  to  Mr.  Hill's 
article  for  further  details  not  covered  herein. 

Geological  Section.  An  idealized  geoloj?ical  section  of  the  Alberhill 
pits,  as  i)repared  by  Mr.  Hill,  is  shown  on  plate  XL  This  sketch  is 
broadly  generalized,  and  may  be  considered  as  a  composite  of  the 
various  beds,  in  their  normal  stratigraphic  sequence.  There  is  perhaps 
no  locality  on  the  property  Avhere  the  series  is  complete,  as  some  of  the 
beds  are  thicker  in  one  i)lace  than  in  another,  and  other  beds  are 
entirely  lacking  in  places.  Burchfiel '  gives  the  following  cross-section 
as  being  fairly  representative : 

Kind  of  strata. 

Soil 

Yellow  top  clay 

Yellow  main  tunnel  clay 


No.  of  feet 

3 
20 

6 
34 

6 

4 

4 
12 


Main  tunnel  clay 

Coal 

Bone  clay  No.  W-105 

Clay  between  bone  and  blue  clays 

Select  west  blue  clay 

West  tunnel  blue  clay 

Shale 


Plate  XII.      Handling  and  storage  of  clay   bv  the   "glory-hole"   method. 
(From  State  Mineralogist's  Report  XIX,  p.  193,  1923.) 

Photos  No.  40,  41,  43  and  44,  all  from  Mr.  Hill's  article,  illustrate 
various  topographic  and  geologic  features  on  the  Alberhill  property. 

Mining  Methods.  Wherever  possible,  the  clays  are  mined  by  open- 
pit  methods.  The  clays  stand  well  in  vertical  banks  up  to  40  or  50 
feet  in  height.  As  operations  are  scattered,  all  loading  is  by  hand. 
Glory-hole  mining  is  used  at  various  places.  Underground  mining  by 
room-and-pillar  methods  is  used  where  the  overburden  is  thick,  or 
where  it  is  desired  to  mine  special  varieties  of  clay  without  removing 
overlying  beds.  In  1926,  extensive  underground  operations  w^ere 
started  for  mining  the  'hill  blue'  clay,  and  it  is  expected  that  most  of 
the  production  of  this  important  variety  will  be  obtained  from  these 
workings  in  the  future,  rather  than  from  open  pits. 

Plate  XII,  by  Hill,  illustrates  the  general  method  of  glory-hole  min- 
ing.     Photos  No.  40,  41,  43  and  44  illustrate  various  features  of  the 

'Burchfiel,  B.  M.,  Refractorv  clavs  of  the  Alberhill,  California,  Deposits:  Jour. 
Amer.  Cer.  Soc,  Vol.  6,  p.  1167,  1923. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


169 


iiiininfr  ojioratinns,  and  photo  No.  42  shows  one  of  the  loading  trestles 
and  bins  Tor  doliveriny  tlic  clay  to  railroad  cars. 

At  many  of  the  pits,  AvheelbarroAvs  are  used  to  deliver  the  clay  to  a 
loading  chute,  from  which  it  is  delivered  by  gravity  into  trucks  for 
hanling  to  the  railroad.  At  otlier  pits,  small  mine  cars  are  loaded  by 
iiand,  and  are  trammed  by  horses  to  the  dumping  points.  In  tlie  glor\' 
holes  and  underground  workings,  mine  cars  are  used.  These  are 
trammed  by  hand,  with  liorses,  or  by  electric  trolle.y  locomotives,  depend- 
ing upon  tlie  length  of  haul  and  average  daily  ]~»rodiiction  nf  the 
woi'kiiig. 

Tlie  total  ])rodiiction  of  clay  from  the  company's  property  is  about 
15,000  tons  annually,  and  prices  (f.o.b.  Alberhill)  range  from  $1.25 
])er  ton  for  the  ])oorer  varieties,  such  as  yellow  stri])ping,  to  $5.50  ])er 
ton  for  some  of  the  selected  varieties  of  white-burning  clay.  .Most  of 
the  varieties  sell  for  $2  to  $3.50  per  ton.  The  clays  enter  into  the 
manufacture  of  a  great  diversity  of  products,  ranging  from  china  to 
lieavy  structural  wares.  The  diversity  of  clays  makes  it  possible  to 
produce  many  specialized  wares.  This  is  particularly  true  of  the 
refractory  and  face-brick  branches  of  the  clay  industry. 

Samples.  Twenty-six  samples  from  this  property  were  tested.  For 
convenience  of  reference,  these  are  grouped  below  according  to  the 
clay  classification  adopted  in  this  rejiort,  which  is  fully  described  in 
Chapter  IV. 


Sample   Record,  Alberhill   Coal   and   Clay  Company. 


Clay 

Clay 

Fircfl 

class 

sample 

Page 

Cone 

color 

number 

number 

reference 

Local  nomenclature 

fusion 

White 

1 

11 

257* 

E-101   china  clay 

28-29 

12 

257* 

E-102  china  clay 

26-27 

2 

15 

264* 

Select  main  tunnel 

30-31 

28 

264* 

SH-3 

30 

29 

264*t 

Main  tunnel   (M.T.) 

30-31 

3 

273 

273*t 

SH-4    (ball  clay) 

34 

Bull 

5 

17 

277*t 

W-105  bone  clay 

34 

23 

277* 

West  blue 

29 

6 

9 

287* 

Hill   blue    (1925) 

29 

14 

287 

A-clay 

31 

27 

287* 

No.    10 

30-31 

272 

292 

Hill  blue,  M.T.    (1926) 

29 

7 

13 

296 

Extra   select  M.T. 

29-30 

271 

301 

Hill   l)lup,   lower  tunnel 

31-32 

274 

302 

Hill  l)lue,  upper  tunnel 

30 

9 

19 

311 

Diamonrl 

23 

2.5 

.•!ll*t 

West  tunnel  blue 

16 

10 

16 

314*t 

Select  west  blue 

18 

Red 

12 

8 

321 

Red  clay  No.   2 

19-20 

18 

321 

Clark  tunnel  mottled 

19 

24 

321 

West  tunnel  mottled 

18-19 

26 

321* 

West  yellow 

not  det. 

13 

7 

328* 

Pink  mottled 

17 

14 

10 

334* 

Hill  blue  green 

14-15 

21 

334 

Sagger 

23 

22 

335 

Yellow  Owl  cut 

17 

*  The  properties  of  the.se  A-arieties  are  also  given  by  Hill,  op.  cit.. 
E-p2   varieties  are  discu.ssed  under  "D.C.  clay." 

t  The  properties  of  these  varieties  are  also  "given  by  Burchfiel,  o;?. 


The  E-101  and 
cit. 


Emsco  Clay  Co.  {Havringion  Pit).  Location:  The  Emsco  Clay 
Company  of  Los  Angeles  has  leased  from  John  Harrington  the  Har- 
rington clay  pit,  in  Sec.  35,  T.  4  S.,  R.  6  W.,  in  the  Temescal  Canon, 
10.5  miles  by  road  southeast  of  the  center  of  Corona,  and  7  miles  by 
road  southeast  of  a  loading  siding  on  the  southeastern  side  of  Corona. 


170 


DIVISION  OF  MINES  AND  MINING 


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CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  171 

Tho  uowly  compU'tetl  raili'oad  connection  I'l'oui  Alberhill  to  Corona 
passes  Avithin  It]  miles  of  the  property.  The  property  under  lease 
comprises  80  acres,  and  lies  on  the  east  side  of  the  valley,  300  feet 
above  its  floor.  It  lias  been  operated  intennittcittly  for  many  years, 
formerly  by  the  now  extinct  Indei)en(lent  Sewer  Pipe  Co.,  wiio  hauled 
the  clay  in  wagons  to  the  Chase  railroad  spur,  south  of  Corona,  for 
shipment  to  Tropico.  Tt  was  later  under  lease  to  the  Alberhill  Coal 
and  Clay  Co..  who  did  not  actively  develop  the  i)i-o])orty,  as  the  com- 
bined transportation  costs  to  Los  Aii<i'eles  were  considerably  greater 
tlian  from  Alberhill,  where  the  principal  dei)Osits  of  this  com])any  are 
located. 

Development  and  Mining:  A  section  of  the  dei)osit,  from  to])  to 
bottom,  as  ex])osed  by  existing:  workings,  is  as  foUoAvs : 

Sample  Test  results 

No.  on  page  Thickness 

Stripping,  of  sandy  soil,  with  some  clay 2-10  feet 

73  323  "Bone"  clay,  over  35%  alumina 4  feet 

71  278  I'ink   mottled 16  feet 

72  328  Red,  high  in  iron 2-  4  feet 

70  272  White,  known  as  select  Harrington  No.  5 7  feet 

69  323  Red  Hor.se   40-.50  feet 

The  clay  beds  arc  ({uite  uniform  in  ({ualitj^,  but  varyin"-  in  thickness 
of  individual  varieties,  over  the  greater  part  of  40  of  the  80  acres  under 
lease.  The  greatest  demand  is  for  the  white  plastic  clay,  but  the  pro- 
duction of  this  variety  is  limited  by  the  amount  of  ])ink  mottled  that 
can  be  marketed.  The  Atlas  Fire  Brick  Comi)any  uses  the  entire  out- 
put of  the  white  plastic  clay.  The  other  clays  are  marketed  to  Los 
Angeles  consumers,  especially  to  Gladding,  McBean  and  Company  and 
to  the  Pacific  Clay  Products  Company. 

The  i)re.sent  (1926-27)  mining  is  being  done  with  a  Thew  tyjie  0, 
f-yd.  gasoline  shovel  in  an  0])en  pit  about  100  feet  square  with  a  40-  to 
50-foot  bank.  Trucks  are  used  to  haul  the  clay  from  the  floor  of  the  pit 
to  a  loading  bin  and  chute  where  it  is  loaded  into  larger  trucks  for  the 
seven-mile  haul  to  the  railroad.  Photo  No.  45  is  a  view  of  the  pit,  and 
No.  46  shows  the  loading  chute. 

Considerable  ciuantities  of  clay  have  been  mined  in  the  i)ast  from 
0]>en  cuts  extending  along  the  east  side  of  the  i)resent  Avorkings,  and 
running  up  the  hill  with  the  clay  which  dii)s  about  10°  to  15°  toward 
the  south.  There  are  several  tunnels  from  these  pits.  To  the  west, 
about  one-quarter  mile  from  the  active  pit,  it  is  extensive  open  cut  and 
chambor  workings  from  Avhich  pink  mottled  and  white  plastic  clay  has 
recently  been  mined. 

Three  to  four  cars  ])er  day  are  being  mined  and  three  men  are 
employed  ;i1  the  pit,  exclusive  of  truck  drivers. 

Gladding,  McBean  and  Companij.  Office  of  Southern  Division  at  621 
S.  Hope  Street,  Los  Angeles.  Through  its  merger  with  the  Los  Angeles 
Pressed  Brick  Conijiany  in  1926,  this  company  now  controls  important 
clay  lands  and  a  clay  working  plant  at  Alberhill,  in  addition  to  the 
Temescal  Tract  already  owned  by  the  company  prior  to  the  merger. 

Alberhill  Clay  Property.  The  clay  property  in  which  the  plant 
is  located  totals  520  acres,  in  Sees.  21  and  22,  T.  5  S.,  R.  5  W.,  as  shown 
on  plate  X  by  legends  L.  A.  P.  B.  Co.  and  L.  A.  P.  Co.  This  property 
adjoins  the  Alberhill  Coal  and  Clay  Company's  property  on  the  east. 


172 


DIVISION  OP  MINES  AND  MINING 


The  main  tunnel  pit  adjoins  the  Alberhill  company's  main  tunnel  pit, 
and  is  shown  on  photos  No.  40  and  47.  Clay  from  this  pit  is  loaded  by 
hand  into  side-dump  mine  cars,  and  hauled  by  electric  trolley  locomo- 
tives across  a  trestle  to  the  plant  on  the  west  side  of  the  railroad,  or  to 
railroad  bins  for  shipment  to  the  Los  Anjreles  plants  of  the  company. 
The  priiicij^al  clay  obtained  from  the  pit  is  main  tunnel  fireclaj^  which 
is  used  in  the  manufacture  of  fii'e  brick. 


Photo  No.  46.     Loading  chute,  Emsco  Clay  Co.     (Harrington 
pit).  Riverside  County. 

About  a  half  mile  southwest  of  the  main  pit  is  the  Sloan  pit,  from 
which  a  number  of  varieties  of  clay  are  produced.  A  representative 
cross-section  of  this  pit  is  given  by  BurchfieP  as  follows: 


No.  of  feet 
40 
30 

6 

4 
50 


Strata 
Overburden  and  j^ellow  top  clay 
Sloan  clay 
Sloan  No.  5  clay 
Sloan  bone  clay   (1923) 
Red  clay 


'  Op.  cit.,  p.  1173. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  17o 

This  j)it  "vvas  still  an  inipoctanl  prnduooi-  when  tlio  ])i'()i)orty  was 
visited  by  the  author  in  l!)^.')  and  l!)2().  The  clay  was  l)('in<i'  mined  by 
hand  methods,  and  was  trans|)orted  to  the  ])lan1  by  aulo  tnu'i\S. 

Various  other  pits  li;ive  been  opened  u|)  l)y  the  e()m])any. 

Sixteen  sam])les  I'l-oiii  the  ))i'0]iei'ly  were  tested.  No.  !)()  1o  100, 
inclusive,  are  i)ractically  all  Irom  the  main  i)it,  and  should  be  com- 
pared with  similar  varieties  from  the  Alberhill  company's  property. 
Xo.  101  to  lOf),  inclu.sive,  are  from  the  Sloan  pit.  For  convenience  of 
refei-ence,  they  are  ari-an<>'ed  in  the  i'ollowinji'  table  accordin.<>'  to  the 
cla\-  classilication  adopted  in  this  report,  which  is  fully  described  in 
Cluii)ter  IV. 

Sample    Record,   Gladding,   McBean   Co.,   Alberhill    Pits. 


Clay 

Clay 

Firefl 

class 

sample 

Page 

Cone 

color 

miiiiber 

number 

reference 

Local  nomenclature 

fusion 

White 

1 

91 

260 

Main  tunnel  sand 

.•!0-31 

103 

260* 

Sloan   bone 

3r> 

2 

90 

265 

Main  tunnel  fireclay 

31 

93 

265 

Select  main  tunnel 

30-31 

3 

96 

272 

No.    10 

32 

98 

272 

Bone   (W-105?) 

35 

Huff 

5 

104 

279* 

No.  5   Sloan 

34-35 

6 

92 

289 

Yellow  main  tunnel 

28 

97 

290 

Smooth   bunker 

31 

102 

290 

Sloan   sand 

29 

7 

101 

298 

Sloan  white 

30 

9 

94 

311 

West  blue 

17 

95 

311 

Select  west  blue 

18 

99 

312 

Tile 

26-27 

Red 

12 

100 

323 

Yellow  stripping 

14  plu 

105 

324 

Sloan  red 

18  plu 

*  Bur(>hfiel,  op.  cit..  p.  1174.  gives  data  on  No.  5  Sloan,  and  states  that  the  Sloan 
bone  is  "iJiactically  identically  the  same  as  the  bone  clay  No.  W-105."  He  also  gives 
data  for  the  yellow  top  clay  from  the  Sloan  pit. 

The  total  clay  production  from  all  of  the  pits  on  the  company's 
Alberhill  property  is  about  500  tons  per  day,  much  of  which  is  .shii)])ed 
to  the  company's  plants  in  Los  Angeles. 

Alberhill  Plant.  The  principal  products  of  the  Alberhill  ])lant 
are  fire  brick  and  other  fireclay  refractories,  face  brick,  and  hollow  tile. 
Hand-molded  roofing  tile  is  also  made.  The  face  brick,  fire  brick,  and 
hollow  tile  are  made  by  the  stift'-mud  process,  after  preparing  the  clays 
in  dry  pans.  Most  grades  of  fire  brick  are  repressed.  Waste-heat 
tunnel  driers  are  used.  All  ware  is  fired  in  round  down-draft  kilns,  of 
which  there  are  twelve,  of  various  sizes  from  32  to  38  feet  in  diameter. 

The  plant  is  well  arranged,  and  well  equipped  to  handle  all  materials 
in  so  far  as  is  feasible. 

A  well-equipped  field  laboratory  is  maintained  for  the  study  of  raw 
materials  and  for  research  on  the  technical  i)roblems  arising  in  the 
l)lant. 

Temescal  Tract.  This  property,  totaling  173  acres,  is  west  of  the 
Emsco  Clay  Company's  property,  0.4  mile  east  of  the  Corona-Elsinore 
highway,  and  25-30  feet  above  the  floor  of  the  valley. 

Development.  The  principal  pit  i.s  800  feet  long,  500  feet  wide  and 
a  maximum  of  150  feet  high.  Red,  pink-mottled  and  blue  plastic  clays 
have  been  mined.  The  varieties  were  apparently  badly  mixed,  and  the 
present  exposures  in  the  face  of  the  bank  do  not  offer  much  encourage- 
ment for  expecting  a  satisfactory  supply  of  uniform  material.     Some 


174 


DIVISION  OP  MINES  AND  MINING 


development  work  is  being  done  in  a  tunnel  at  an  elevation  about  100 
feet  higher  than  the  pit  and  it  is  stated  that  good  clays  were  found 
underlying  the  Emsco  clays. 

At  the  times  of  visit,  in  1925  and  11)26,  the  ])it  was  idh',  but  was  being 
held  in  reserve  for  the  future. 

/.  D.  Hoff,  of  Elsinore,  owns  a  cla}'  property  in  Sec.  22,  T.  5  S.,  R. 
5  W.,  on  which  some  prospecting  has  been  done,  by  core-drilling  and 


Photo  No.  4  7.  Gladding,  McBean  and  Company  (formerly 
Los  Angeles  Pressed  Brick  Company),  .A.lberhill, 
Riverside  County.  Main  tunnel  pit  leased  from  the 
Alberhill  Coal  &  Clay  Company.  (See  also  photos 
No.  40  and  41.) 

test-pitting.  A  number  of  samples  were  sent  to  the  Stanford  labora- 
tory by  Mr.  Hoff,  but  none  of  these  were  large  enough  to  test.  The 
general  appearance  of  some  of  the  samples  is  the  same  as  that  of  certain 
clays  from  other  properties  in  the  district.  Mr.  Hoff  expects  to  build 
a  clay-working  plant  near  Alberhill  in  the  near  future. 

Los  Angeles  Brick  Co.  Gustave  Larsen,  director  in  charge  of  opera- 
tions ;  Harvey  Gardner,  plant  superintendent  at  Alberhill.  Main  office, 
1078  Mission  Road,  Los  Angeles.     This  company  acc^uired  the  holdings 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


175 


of  the  former  California  Clay  Maiiiifaetnrint:  Company  in  the  Alberhill 
district,  and  built  a  plant  at  AlborJiill  in  ^\)27)  for  tlie  manufacture  of 
face  brick,  fire  brick,  roofino-  file,  floor  tile,  and  hollow  tile.  The  manu- 
facture of  other  products  is  contemplated  by  the  company. 

The  pi-oi)erty  at  Alberhill  consists  of  the  SEj  and  the  E^  SW^ 
Sec.  21,  T.  5  S!,  R.  5  W.,  S.  B.  M.,  and  other  nearby  property  totalinj? 
720  acres.  This  lies  to  the  west  of  the  principal  holdings  of  the  Los 
Angeles  Pressed  Brick  Co.  Most  of  the  clays  that  are  being  mined  at 
]iresent  are  from  the  western  limb  of  the  synclinal  trough  in  which  the 
clays  of  the  district  lie.  The  clays  include  most  of  the  varieties  that 
typify  the  Alberhill  district,  and  occur  in  the  same  irregular  fashion, 
without  notable  continuity  of  individual  strata.  There  is  apparently, 
however,  a  more  extensive  dei)osit  of  high-grade  bone  clay  on  this 
property  than  in  any  otlier  known  locality  in  California. 

Clay  Deposits:  A  numbei-  of  ])its  have  been  oi)ened  on  the  property, 
but  at  the  time  of  visit,  in  July,  1925,  and  September,  1926,  it  was  not 
])ossible  with  the  data  at  the  writer's  disjjosal  to  definitely  establish 
the  stratigrai)hic  correlations  between  the  various  pits,  nor  between  the 
nearby  pits  of  other  operators.  A  number  of  samples  were  taken  on 
botli  occasions.  No.  74  to  87,  inclusive,  were  taken  in  1925,  and  No.  229 
to  2:52  inclusive,  in  1926.  Vertical  sections  through  the  "East," 
"West,"  and  "Main"  pits  are  given  in  the  following  tables.  Photo 
No.  52  shows  the  East  pit  as  it  ap])eared  in  September,  1926. 


Sample 
No. 


230 


Page 
No. 


300 


Vertical  Section,  East  Pit,   Los  Angeles   Brick  Co. 

(From  top  to  bottom.) 

Local  name  Thioknoss. 

or  number  Principal  uses  fi'f  t 

Stripping                Sometimes  for  face  brick 0-10 

Pink-mottled        Face  brick,  tile ir)-20 

No.    1   red               Face  brick,  tile 10 

No.   9                      Fire  brick IT) 


Sample 

Page 

No. 

No. 

81 

289 

76 

28S 

77 

27S 

711 

278 

so 

297 

7S 


2S8 


Vertical   Section,  West   Pit,   Los  Angeles   Brick   Co. 

(From  top  to   Ixittom.) 

Local  name  Thickne.ss. 

or  number                    Principal  uses  feet 

Tile  clay               Hollow  tile,  roofing  tile 6 

No.   2.')                     Fire  brick  and  pottery 10 

No.   23                     Fire  brick  and  pottery 10 

No.   20                    Pressed  brick,  fire  brick 20 

Fireclay                 Firebrick 10 

Plasti<-  pink 

and  yellow        Fire  brick  and  i)ottery ? 

No.   lO'                    Fire  brick 20 


Vertical  Section,   Main    Pit,   Los  Angeles   Brick   Co. 

(From   top  to  bottom.) 

Sample  Page  Local  name  Thickness, 

No.  No.  or  number                    Principal  uses  feet 

S.'')  298  Pink  mottled  Fire  brick,  sewer  pipe,  tile,  pottery —  Up  to  30  ft. 

86  279  No.   26  bone  Fire  brick 6 

85  298  Pink  mottled  See  above Up  to  10  ft. 

83  297  Red  clav  Hollow  tile,  roofing  tile 12-15 

84  289  P.  M.  fireclay  Fire  brick 10-20 

A  number  of  samples  were  taken  from  undeveloped  or  partially 
develoi)ed  beds.  For  convenience,  these  are  given  in  the  following 
table : 


176  DIVISIOX  OF  MINES  AND  MINING 

Miscellaneous  Samples.      Los  Angeles   Brick  Co. 

Thick- 
Sample       Page  Local  name         Name  of  pit  from  wliicli  ness. 
No.              No.                or  number                sample    was    taken            Principal  uses      feet 

74  278  West  bone  West  bone  pit  Fire  brick 4-  6 

75  335  Red  No.   2  West  bone,  underlying       Tiie  and   face 

No.  7  1                                        brick ? 

87  279  Smooth  bone  100  yd.  E.  of  main  pit, 

overlving  No.  86               Fire  brick 15 

232               281              Smooth  bone                 ?      '                                   Fire  brick 6 

231  281  High-alumina 

bone                             ?                                         Fire  brick 4 

82               315              Clay  shale               Blue  pit  Tile  and  f  a  c  e 

brick 10-20 

229               300             No.   7                        No.  7  pit                                 Fire  brick 34 

Note. — Samples  No.  231  and  232  were  supplied  by  Mr.  Gardiner  in  Septeml)er,  192(;. 
Name  of  pit  from  which  sample  was  taken   was  not  given. 

The  areal  extent  of  these  various  clays  can  not  be  definitely  deter- 
mined in  the  absence  of  core-drilling-  data.  Enough  evidence  is  at 
hand,  however,  to  warrant  the  statement  that  many  of  the  beds  are 
practically  continuous  over  areas  in  excess  of  -300  acres,  although  it  is 
doubtful  if  the  clay  in  an  individual  stratum  will  be  uniform  in  quality 
over  such  an  area. 

Mining:  The  clay  is  mined  from  the  various  open  pits  by  hand 
methods  and  is  transported  to  the  plant  by  auto  trucks. 

Plant  :  Face  brick,  both  plain  and  ruffled,  is  the  principal  product 
of  the  Alberhill  ])lant.  Fire  brick  is  being  made  in  increasing  amounts, 
and  a  special  high-alumina  fire  brick  is  being  manufactured  from  the 
bone  clays  that  occur  on  the  property.  Photos  No.  48  to  51  show 
various  views  of  the  plant,  and  photo  No.  52  is  a  view  of  the  east  pit. 

The  clays  as  they  are  received  from  the  pits  are  ground  in  dry  pans, 
and  elevated  to  separate  steel  bins  for  each  variety  of  clay.  From  the 
bins,  disc  feeders  are  used  to  feed  an  augur  machine,  which  is  equipped 
with  an  automatic  cutter.  Repressing  is  applied  on  ware  that  requires 
it.     A  32-tunnel  waste-heat  drier  operates  on  a  48-hour  cycle. 

Firing  is  done  in  four  32-ft.  and  eight  34-ft.  round  down-draft  kilns, 
fired  with  air-atomized  oil.  Buff  and  cream  face  brick  and  all  firebrick 
are  fired  to  cone  11,  and  red  face  brick  are  fired  to  cone  10.  Four  daj's 
is  allowed  for  firing,  four  days  for  cooling,  three  days  for  drawing, 
and  two  days  for  setting.  Each  Iciln  is  therefore  fired  about  twice  a 
month. 

One  hundred  and  twenty-five  men  are  employed  in  the  plant,  and 
twenty  in  the  pits. 

Pacific  Clay  Products  Company.  Robt.  Linton,  general  manager, 
1151  S.  Broadway  Street,  Los  Angeles.  This  company-,  which  has  a 
number  of  manufacturing  plants  in  Los  Angeles  County,  owns  and 
operates  several  clay  proi)erties  in  Riverside  County.  The  location  of 
the  properties  in  the  Alberhill-Corona  district  is  shown  on  plate  X, 
page  162. 

Douglas  Pit.  This  is  an  80-acre  tract  consisting  of  the  Ni  of  NE^ 
Sec.  22,  T.  5  S.,  R.  5  W.,  S.  B.  M.,  adjoining  the  active  pits  of  the 
Alberhill  Coal  and  Clay  Co.  on  the  north.  A  view  of  the  pit  is  shown 
in  photo  No.  53.  The  pit  is  mined  by  hand  methods,  using  shovel  and 
wheelbarrow  to  deliver  the  clay  to  small  loading  chutes  for  loading  the 
trucks  which  haul  it  to  the  railroad  bins. 


177 

111(1  llie 
'scribed 
"om  top 


11 


uction. 


r^. 


.JjC, 


driers, 


Thickness 
of  bed, 
feet 
5 
4 
7 
50-70 


176  DIVISION  OF  MINES  AND  MINING 

Miscellaneous  Samples.      Los  Angeles   Brick  Co. 

Thick - 
Sample        Pago  Local  name         Namo  of  pit  from  whicli  ne.ss. 

No.  No.  or  number  sample    was    taken  Principal  uses      feet 

74  278  West  bone  West  bone  iiit  Fire  brick 4-  6 

75  335  Red  No.   2  West  bone,  underlying       Tiie  and  face 

No.  7  1                                        brick ? 

87  279  Smooth  bone  100  yd.  E.  of  main  pit, 

overlying  No.  86               Fire  brick 15 

232               281              Smooth  bone                 ?                                         Fire  brick 6 

231  281  High-alumina 

bone                              ?                                           Fire  brick 4 

82               315              Clay  shale               Plue  pit  Tile  and  face 

brick 10-20 

229                300              No.   7                          No.  7  pit                                   Fire  l)rick 34 

Note. — Samples  No.  231  and  232  were  supplied  by  Mr.  Gardiner  in  September,  192(;. 
Name  of  pit  from  which  .sample  was  taken   was  not  given. 

The  ureal  extent  of  these  various  elays  can  not  be  definitely  deter- 
mined in  the  absence  of  core-drilling  data.  Enough  evidence  is  at 
hand,  however,  to  warrant  the  statement  that  many  of  the  beds  are 
practically  continuous  over  areas  in  excess  of  300  acres,  although  it  is 
doubtful  if  the  clay  in  an  individual  stratum  -will  be  uniform  in  quality 
over  such  an  area. 

Mining  :  The  clay  is  mined  from  the  various  open  pits  by  hand 
methods  and  is  transported  to  the  plant  b}^  auto  trucks. 

Plant  .-  Face  brick,  both  plain  and  ruffled,  is  the  principal  product 
of  the  Alberhill  ]ilant.  Fire  brick  is  being  made  in  increasing  amounts, 
and  a  special  high-alumina  fire  briclv  is  being  manufactured  from  the 
bone  clays  that  occur  on  the  property.  Photos  No.  48  to  51  show 
various  views  of  the  plant,  and  photo  No.  52  is  a  view  of  the  east  pit. 

The  clays  as  they  are  received  from  the  pits  are  ground  in  dry  pans, 
and  elevated  to  separate  steel  bins  for  each  variety  of  clay.  From  the 
bins,  disc  feeders  are  used  to  feed  an  augur  machine,  which  is  equipped 
with  an  automatic  cutter.  Repressing  is  applied  on  ware  that  requires 
it.     A  32-tunnel  waste-heat  drier  operates  on  a  48-hour  cycle. 

Firing  is  done  in  four  32-ft.  and  eight  34-ft.  round  down-draft  kilns, 
fired  with  air-atomized  oil.  Buft"  and  cream  face  brick  and  all  firebrick 
are  fired  to  cone  11,  and  red  face  brick  are  tired  to  cone  10.  Four  days 
is  allowed  for  firing,  four  daj^s  for  cooling,  three  days  for  drawing, 
and  two  days  for  setting.  Each  kiln  is  therefore  fired  about  twice  a 
month. 

One  hundred  and  twenty-five  men  are  employed  in  the  plant,  and 
twenty  in  the  pits. 

Pacific  Clay  Products  Coinpany.  Robt.  Linton,  general  manager, 
1151  S.  Broadway  Street,  Los  Angeles.  This  company,  which  has  a 
number  of  manufacturing  plants  in  Los  Angeles  County,  owns  and 
operates  several  clay  properties  in  Riverside  County.  The  location  of 
the  properties  in  the  Alberhill-Corona  district  is  shown  on  plate  X, 
page  162. 

Douglas  Pit.  This  is  an  80-acre  tract  consisting  of  the  N^  of  NE^ 
Sec.  22,  T.  5  S.,  R.  5  W.,  S.  B.  M.,  adjoining  the  active  pits  of  the 
Alberhill  Coal  and  Clay  Co.  on  the  north.  A  view  of  the  pit  is  shown 
in  photo  No.  53.  The  pit  is  mined  by  hand  methods,  using  shovel  and 
wheelbarrow  to  deliver  the  clay  to  small  loading  chutes  for  loading  the 
trucks  which  haul  it  to  the  railroad  bins. 


al  view  of  AlbeihiU  plant,    L<.s  Angeles  Brick  Company.      (Plioto  by  cuuile-sy  uf  the  coinpanjj 


176 

IV 


Sample 
No. 

Page 
No. 

74 
75 

278 
335 

87 

279 

232 
231 

281 
281 

82 

315 

229 

300 

Note.- 
Name  of 

-Sample.= 
pit  from 

The  areal  ex 
mined  in  the 
hand,  hoAvever 
practically  con 
doubtful  if  the 
over  such  an  a 

Mining:  Th 
methods  and  ii 

Plant:  Fac 
of  the  Alberhi 
and  a  special 
bone  clays  th; 
various  views 

The  clays  as 
and  elevated  t 
bins,  disc  feed 
with  an  autora 
it.     A  32-tuni 

Firing  is  dc 
fired  with  air- 
are  fired  to  CO 
is  allowed  foi 
and  two  days 
month. 

One  hundn 
twenty  in  the 

Pacific  Cla 
1151  S.  Broa 
number  of  n 
operates  sevei 
the  propertie 
])age  162. 

Douglas  P 
Sec.  22,  T.  5 
Alberhill  Co£ 
in  photo  No. 
wheelbarrow 
trucks  which 


f'LAY  RESOURCES  AND  CERAMIC  INDUSTRY 


177 


The  clays  are  similar  to  those  on  the  adjoining  Alberhill  and  the 
Gla(hlin^',  MeBean  properties.  Pour  samples  were  taken,  as  described 
in  the  foHowiiijr  tab)*',  wliich  is  arranged  as  a  vertical  section  from  top 
to  bottom  oi'  the  known  ileposits: 


Photo  No.  49.     Los  Angeles  Brick  Company,  Alberhill  plant,  during  construction. 

Riverside  County. 


Photo    No.    50.     Los    Angeles    Brick    Company,    Alberhill    plant,    tunnel    driers, 
during  construction.     Riverside  County. 


Sample 
number 

Page 
reference 

Clay 
class 
number* 

Local  nomenclature 

Thickness 
of  bed, 
feet 

108 
109 
110 
111 

290 
266 
298 
315 

6 
> 

7 
10 

Upper  Douglas 
Douglas  main  tunnel 
Douglas 
Lower  Douglas 

5 
4 

7 
50-70 

*  Refers  t 

o  clay  classificat 

ion,  described 

fully  in  Chapter  IV. 

12 — 54979 


178 


DIVISION  OF  MINES  AND  MINING 


Hoist  Pit.  Tliis  is  a  40-aere  property,  consisting  of  the  NE^  of  NE:^ 
Sec.  26,  T.  f)  S.,  K.  5  W.,  and  lies  soutlieast  of  the  active  workings  of  the 
Alberhill  company.  The  principal  varieties  of  clay  exposed  in  this  pit 
are  known  as  Hoist  Pit  blue  (sample  No.  112,  p.  324)  and  Hoist  Pit 


Photo   No.    51.      Lo.s   Angeles   Brick    Company,    Alberhill   plant, 
showing'  drier  cars  and  brick  represses.     Riverside  County. 


red  (sample  No.  113,  p.  324).  The  blue  clay  is  about  40  feet  thick  and 
overlies  the  red  clay,  which  is  about  the  same  thickness.  Both  varieties 
are  red-burning  plastic  clays,  of  particular  value  in  the  manufacture  of 
sewer-pipe. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


179 


McKnicht  Clay  Pit.  The  ]MeKniy:]it  clay  i)it,  :^5  miles  by  road 
soiitlnvest  of  Corona,  liiverside  Connly,  in  Sees.  ;>,  I)  and  10.  T.  4  S., 
R.  7  W..  S.  T>.  il.,  has  been  known  and  worked  for  over  :{()  years. 

Description  of  Dejiosit  and  "\Vorkin<is.  The  dei)osit  is  composed  of 
two  typical  varieties  of  clay ;  an  ui)i)er  bed,  60  feet  thick,  of  red- 
burning  plastic  clay,  used  in  the  manufacture  of  sewer  pipe,  electric 
conduit,  and  hollow  building  tile,  and  a  lower  bed  of  fire  clay,  30  feet 
thick,  used  for  fire  brick  and  flue  lining.  The  sewer-pipe  clay  is  repre- 
sented by  sample  No.  GG,  i)age  277,  and  the  fireclay  by  sami)le  No.  67, 
page  277.     From  2  to  4  feet  of  stripping  overlies  the  clay  beds. 

The  present  workings  attack  the  clay  beds  from  exposures  on  the 
northerly  side  of  a  steep  hill,  into  which  the  clay  dips  at  an  angle  of 
a|)])roximately  35°.  The  fire  clay  is  mined  through  a  lower  tunnel, 
410  feet  long,  having  its  portal  500  feet  east  of  an  upper  tunnel  and 


,f* 


u^.*^<^ 


y  '-.-*f.  «*' 


■«"-■' 


Photo  No.   52.     East  pit,  Los  Angeles  Brick  Co.,  Alberhill,  Riverside  County. 

70  feet  lower  in  elevation.  The  two  tunnels  are  connected  by  a  raise, 
and  clay  is  mined  by  room  and  ])illar  methods,  dumped  into  the  raise, 
and  drawn  off  into  small  mine  cars  in  the  lower  tunnel.  The  rooms  in 
which  the  fire  clay  is  mined  are  about  15  feet  high,  and  connect  with 
an  open  pit  and  tunnel  at  a  still  higher  level  from  which  the  red  sewer 
pipe  clay  is  being  mined.  P^xtensive  workings  of  a  similar  character, 
especially  to  the  southeast,  attest  the  active  mining  of  this  deposit  over 
a  long  period  of  years.  The  southeastern  portion  of  the  deposit  has 
been  exhausted.  It  is  known  that  the  fire  clay  pinches  out  to  the  west- 
ward, but  there  is  apparently  a  good  tonnage  of  the  sewer-pipe  clay 
remaining. 

All  mining  and  loading  is  hy  hand  methods.  Each  of  the  two  work- 
ing levels  is  equipped  with  a  bin  for  receiving  the  clay  from  small  mine 
ears  and  storing  it  for  the  light  truck  which  is  used  for  hauling  1.7 
miles  to  a  siding  ^^n  the  southeastern  edge  of  Corona.  At  the  time  of 
visit,  July  16,  1925,  the  output  was  50  tons  per  day,  of  each  clay. 


180 


DIVISION  OP  MINES  AND  MINING 


WiLDOMAR  Kaolin  Deposit.  ''iMie  Pacific  Cbiy  Products  Coinjjany 
owns  a  deposit  of  non-plastic,  (|iiartzose,  whito-bunrm^'  kaolin  located 
^  mile  east  of  the  Inbuul  Highway,  fi-oni  a  jioint  2.(i  miles  southeast  of 
Wildonuir.  The  ])roperty  comprises  18  acres,  in  It.  'A  W.,  T.  7  S., 
S.  B.  M. 

The  material  has  been  exposed  by  stripping-  in  two  places,  about 
150  feet  apart.  It  lies  in  a  bed  from  80  to  42  inches  thick  dipping  30° 
west,  forming  tlie  side  slo])e  of  a  low  hill  that  rises  above  the  valley 
floor.     The  southerly  exposure  is  100  feet  long,  and  has  been  mined 


Photo  No.  53.     Douglas  pit,  Pacific  Clay  l^rocUicts  Comisany 
at  Alberhill,  Riverside  County. 

for  50  to  60  feet  above  the  valley,  and  for  a  length  of  50  feet.  A  shaft 
has  been  sunk  to  follow  the  bed  beneath  the  valley  floor.  Access  to  the 
shaft  was  not  convenient  at  the  time  of  visit  on  July  21,  1925.  The 
northern  exposure  is  70  feet  long  by  50  feet  wide,  and  about  half  of 
the  exposed  material  has  been  mined. 

A  thin  layer  of  debris  overlies  the  deposit,  so  that  tracing  beyond  the 
stripped  exposures  is  not  possible  without  excavation  or  boring. 

^Miscellaneous  Properties.     The  company  also  owns  the  following 
j)roperties  in  the  Alberhill  district :  Quintet,  consisting  of  88.79  acres, 


CLAY  KESOUKl'ES  AND  C'EKA.MU     l.NDUSTHV  181 

ill  tlie  W.',  XWj  Sec.  26,  and  El  Sobrantc,  160  acres,  coinprisinu:  the 
XEi  Sec. '26,  both  in  T.  4  S.,  R.  6  W. ;  Tenicscal  Sixtv,  60  acres/ com- 
prising the  \W1  NW]  and  Ni  NEj  XW]  S(>c.  12.  T.  5  S.,  R.  6  W. ; 
Terra  Cotta  Ei<rhty,  HO  acres,  comprising-  the  Wi  SW{  Sec.  26,  and 
Terra  Cotta  Plant  Site,  40  acres,  comi)risino:  the  NE^  SW^  See.  26,  in 
T.  5  S.,  R.  5  W.  Ill  addition,  the  company  owns  a  lialf  interest  with 
GladdinjTr,  McDcaii  and  ("omijanv  in  the  Elsinore  Joint  Proijcrty,  120 
acres,  comprising;  the  W^  NE^  and  the  SE{  NEj  Sec.  26,  T.  5  S.,  R. 
5  W.     Little  or  no  development  work  has  been  done  on  these  i)roperties. 

Hancoch's  Brick  Yair].^  C.  V.  Hancock  and  Son,  owners.  l.'?.'}0  Lemon 
Street,  Riverside.  This  yard,  for  the  mannfaeture  of  common  red 
brick  only,  is  located  on  the  southern  outskirts  of  the  city  of  Riverside. 
Clay  is  mined  with  a  steam  shovel  from  a  10-  to  20-foot  bank  of  red  clay 
near  llie  plant.  The  brick  are  molded  by  Ili(>  stiff'-mud  ])r()cess,  and 
fii'ed  in  jias-tired  field  kilns.  The  capacity  of  the  plant  is  4o,000  brick 
per  day.  The  len<>th  of  the  operating  season  tlepends  upon  local 
demand.     Twenty  men  are  employed. 

Prado  Tile  Company.  Losse  and  Romedas,  owners.  At  Prado,  two 
miles  west  of  Corona.  This  is  a  i)lant  for  manufacturing  hand-made 
roofing  tile  and  Jlexican  pottery.  The  clay  is  mined  from  a  local  deposit 
and  is  ])ugged  by  treading.  The  ware  is  di'ied  in  air.  and  is  fired  in 
an  oil-fired,  rectangular  up-draft  kiln,  holding  about  1000  tile  (4 
.squares  of  100  square  feet).  About  10  men  are  employed  at  the  plant 
when  operating.  The  price  of  the  tile,  at  the  i)lant,  was  $17  ])er 
square  in  1926. 

Temescal  Water  Company.  ( i)  A  small  i)it  in  ])ink-mottled  clay 
was  opened  up  during  the  season  of  1926  on  a  projierty  in  Sec.  35,  T. 
4  S.,  R.  6  W.,  about  a  mile  southwest  of  the  Emsco  pit.  The  ownership 
of  the  property  could  not  be  determined,  as  no  work  was  being  done  at 
the  time  of  visit,  in  Se])tember,  1926.  It  is  said  to  belong  to  the 
Temescal  Water  Comi)any,  and  that  it  was  being  develoi)ed  by  'Doc' 
Meyers.  The  pil  had  lieen  ojiened  by  an  o])en  cut,  25  feet  wide  and  40 
feet  long.  A  horse  scrajier  was  used  for  removing  overburden,  and  the 
clay  was  mined  by  hand  methods.  The  only  clay  exi)osed  was  ]iink 
mottled,  a  sample  of  which  was  taken.  See  No.  218,  ])age  .'529.  The 
extent  of  the  deposit  could  not  be  determined,  but  the  clay  could  be 
traced  around  tlx^  liill  for  a  distance  of  about  200  yards. 

J.  W.  Wilson  of  Vidal,  a  station  on  the  Parker  cut-off  of  the  Santa 
Fe  Railroad,  in  San  Bernardino  County,  has  located  26  claims  on  an 
extensive  clay  deposit  in  a  playa  three  miles  by  road  .south  of  Vidal  in 
Riverside  County. 

The  clay  varies  in  color  from  nearly  white  to  pinki.sh  and  blue-grey. 
The  beds  have  a  total  thickness  of  at  least  20  feet  over  the  entire  area, 
excei)t  where  recent  erosion  has  removed  portions  of  the  deposit.  In 
many  places,  however,  thin  beds  of  unconsolidated  sandstone,  from 
less  than  inch  to  .several  inches  in  thickness,  are  interbedded  with  clay 
beds  from  one  to  three  feet  in  thickness.  The  sandstone  beds  contain 
many  poorly  i)reserved  fossils.  notal)ly  sharks  teeth,  and  small  clam 
shells  less  than  an  inch  in  diameter.  The  clav  beds  are  overlain  by 
varying  thicknesses  of  loosely  consolidated  sand  and  fine  gravel,  but 

»  Supplemented  by  data  obtained  by  W.  B.  Tucker,  November,  1927. 


182  DIVISION  OF  MINES  AND  MINING 

there  are  large  areas  where  erosion  has  removed  practically  all  of  this 
capping,  and  has  exposed  the  clay  beds. 

Samples  No.  42  and  43  were  taken  for  test.  The  results,  given  on 
])age  :U0,  indicate  that  tlie  clay  is  unsuited  for  general  ceramic  pur- 
poses, although  its  extremely  fine  grain,  and  high  plasticity,  may  indi- 
cate certain  special  uses. 

Bibl  (Clay  resources  of  Riverside  Countv)  :  State  ]\Iining  Bureau 
Bull.  38,  pp.  221-224  and  252-253;  Prel.  Kept.  7,  pp.  74-91. 
Kept.  XV,  pp.  559-574;  XIX,  pp.  185-219.  Also  Jour.  Amer. 
Cer.  Soc,  Vol.  6,  pp.  1167-1175,  1923. 

SACRAMENTO   COUNTY. 
(By  C.  A.  Logan  and  W.  F.  Dietrich.)' 
General    Features. 

Sacramento  County  is  almo.st  in  the  geographic  center  of  the  state, 
and  lies  principally  in  the  Great  Central  Valley,  with  the  eastern 
])art  of  the  county  rising  into  the  foothills  of  the  Sierra  Nevada  Moun- 
tains. The  elevation  varies  from  30  feet  above  sea  level  at  Sacra- 
mento (Southern  Pacific  depot)  to  about  900  feet  above  the  sea  on  the 
east  side  of  the  foothills.  The  Sacramento  and  American  rivers  unite 
just  northwest  of  Sacramento  city  limits,  the  former  flowing  south  and 
forming  the  western  county  line.  Cosumnes  River  traverses  the  south- 
eastern part  of  the  county,  flowing  into  Mokelumne  River  on  the 
southern  county  line. 

The  county  and  capital  city  are  served  by  two  transcontinental  rail- 
ways, the  Western  Pacific  and  Southern  Pacific,  which  cross  the  county 
from  north  to  south.  The  Central  California  Traction  Company's  line 
from  Sacramento  to  Stockton  connects  with  the  Santa  Fe  system, 
and  the  San  Francisco-Sacramento  electric  railway  runs  southwest 
to  Oakland  and  San  Francisco.  A  third  electric  interurban  line,  the 
Sacramento  Nortliern,  run.s  north  as  far  as  Chico.  Three  regular 
steamer  lines  ply  between  Sacramento  and  San  Francisco  on  the  river, 
giving  freight  and  passenger  service,  besides  which  there  are  numerous 
other  river  cargo  carriers.  Two  large  power  companies.  Pacific  Gas  and 
Electric  Company  and  Great  Westcn-n  Power  Company,  supply  electric 
power,  and  the  former  company  and  Sacramento  Gas  Company  supply 
gas.  Transportation  and  power  needs  are  thus  well  supplied.  State 
highways  radiate  in  all  directions  from  Sacramento. 

Sacramento  County  has  been  an  important  gold-producing  district 
for  a  long  time.  Previous  to  the  enactment  of  the  anti-debris  laws 
there  was  considerable  hydraulic  mining  in  the  Folsom  district  and 
the  gold  production  from  this  source  and  from  drift  mining  was  as 
high  as  half  a  million  dollars  a  year.  In  1899  gold  dredging  began  and 
gold  production  reached  its  peak  between  1909  and  1919,  the  maximum 
yield  being  over  two  and  a  half  million  dollars  in  1919.  From  now  on, 
production  from  the  gold  dredges  will  decline  rather  rapidly. 


'  Ml-.  T.i()Kan'.s  report  on  Sacramento  t'uunty  \va.s  made  in  1925.  See  State  Min- 
eralogist's Report  XXI,  pi>.  1-22.  Mr.  Dietrich  visited  some  of  tlie  clay  plants  in  the 
county  iti  1925  and  192ii  and  has  added  certain  details  to  Mr.  Logan's  descrijitions, 
especiall.v  to  that  referring  to  the  Natoma  Clay  ComiJany.  He  also  added  notes  on 
the  Michigan  Bar  clay  deposits.  In  1927.  Mr.  Logan  visited  the  plant  of  the  Valley 
Brick  Company,   and   supplied   the   description   that   is   included   here. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  183 

As  a  hy-jiroduct  industry,  ntiliziup'  tho  waste  rock  ])iles  of  the 
(Ired^red  laud,  tlie  roek-cfusliino-  industry  has  become  important  and  has 
jrrown  rapidly  with  the  increased  use  of  concrete.  Sand  and  gravel  are 
also  dredged  in  large  quantities  from  the  American  River  bed. 

Brick,  tile,  and  a  great  variety  of  clay  products  are  produced,  using 
local  clay  mostly.  Natural  ga.s  is  supplied  for  domestic  use.  in  part 
from  wells.  Granite  is  quarried,  and  ])latinum  metals  and  silver  are 
recovered  as  by-products  of  dredging. 

Clay    Resources. 

A  few  deposits  of  high-grade  clay  occur  in  the  southeastern  part  of 
the  county,  adjoining  Amador  County.  These  are  part  of  the  lone 
formation,  which  is  so  productive  of  clays  in  the  vicinity  of  lone.  Tlie 
deposits  were  worked  a  number  of  years  ago,  and  were  the  basis  for 
establishing  one  of  the  first  clay-working  plants  in  California,  but  have 
been  idle  for  many  years,  and  present  exposures  are  insufficient  to 
warrant  development",  in  view  of  the  lack  of  cheap  transportation 
facilities  in  this  area. 

There  are  adequate  supi)lies  of  common  clay  in  the  county,  suitable 
for  the  manufacture  of  red  structural  ware.  The  gold-dredge  silt  now 
being  mined  by  the  Natoma  Clay  Company  is  of  particular  interest. 
The  proximity  to  the  important  de]iosits  of  high-grade  clays  of  Lincoln, 
Placer  County,  and  lone.  Amador  County,  has  encouraged  the  estab- 
lishment of  a  number  of  clay  plants  in  or  near  Sacramento. 

Cannon  and  Company  (formerly  Sacramento  Clay  Products  Com- 
pany). Owner,  Cannon  and  Company,  a  close  corporation.  D.  A.  Can- 
non, president  and  general  manager.  IMain  office.  400  Forum  Building, 
Sacramento.  The  plant  and  clay  beds  are  at  Ben  Ali  siding,  four 
miles  from  Sacramento,  on  what  was  formerly  a  part  of  Rancho  del 
Paso,  adjoining  the  Southern  Pacific  main  line  and  state  highway. 
There  are  about  two  hundred  acres  in  the  holdings.  A  view  of  the 
plant  is  shown  on  photo  No.  54. 

About  sixtv  per  cent  of  the  clay  used  in  the  plant  is  mined  on  the 
property.  White  clay  and  sand  are  brought  from  Lincoln  and  lone 
deposits  for  making  fire  brick  and  are  mixed  in  desired  projiortions 
with  the  local  clay  for  making  other  products. 

The  clay  on  the  property  is  a  firmly  consolidated  yellowish-brown 
sandy  clay,  red-burning,  and  locally  called  'hardpan.'  It  is  covered 
by  alayer  of  reddish  sandy  loam,  which  is  worked  and  marketed  sepa- 
rately for  molding  sand.  The  'hardpan'  layer  varies  in  thickness  but 
the  entire  bank  is  similar  in  quality,  and  is  worked  to  a  depth  of  fifteen 
to  twenty  feet. 

Clay  is  dug  by  a  steam  shovel  and  horse  scrapers,  loaded  in  cars  and 
hoisted  to  the  plant,  where  it  is  dumped  and  aged  under  cover.  It  is 
fed  by  an  auger  feed  to  two  dry  pans  for  grinding,  after  which  a 
bucket  elevator  lifts  it  to  a  Hum-Mer  electric  screen,  screening  to  the 
desired  size  dei)ending  on  the  ])roduct  to  be  made.  The  clay  then 
passes  to  storage  biiis,  pug-mills,  and  brick  or  tile  machines.  The  stiff- 
mud  i)rocess  is  used.  The  pr(»ducts  manufactured  iiiclude  face  brick, 
interlocking  and  hollow  tile,  fii-e  brick,  hollow  tile,  Roman  brick  and 
other  special  shapes  and  sizes.  The  shrinkage  of  the  local  clay  is  one 
in  thirteen,   which   is  low  comi)ared  with  the  Avhite  clays  used,   and 


184 


DIVISION  OP  MINES  AND  MINING 


CLAY  RESOURCES  AM)  CERAMIC  INDUSTRY  1  So 

shrinkajre  of  different  ])ro(luc*ts  varies  -with  iiroiiortiniis  of  the  elays 
employed.  Fusibility  of  the  fire  briek  is  above  :W(W  Fahrenheit  and 
the  face  briek  2100  to  2200-  Fahreidieit.  P'or  burninfr  the  brick  and 
tile  there  are  five  down-draft  round  kilns,  each  with  a  capacity  of 
70,000  to  80.000  bricks.  The  bricks  are  burned  five  days  and  tile  two 
and  one-half  to  three  days.  Clay  workinp-  machinery  is  o])erated  from 
a  main  drive,  usinji-  a  20()-h.p.  electric  motor,  and  crude  oil  fuel  is  used 
for  the  kilns  and  steam  shovel.  There  is  a  spur  track  to  the  plant  from 
the  railroad  main  line.  Tliirty-five  to  forty  men  are  emi)loyed  and  tlic 
jdant  has  a  cai)aeity  of  10,000  to  12.000  tons  a  month. 

Interlocking'  tile  is  used  for  bearing  walls.  This  tile  and  the  face 
brick  have  been  used  in  the  new  California  State  Life  Building  and  in 
other  large  buildings  recently  erected  in  Sacramento. 

Bibl:  State  Mineralogist's  Reports  XV,  ]).  404;  XXT,  p.  7. 

Michigan  liar  Claij  Deposits.  In  the  vicinity  of  ^Michigan  Bar.  6..") 
miles  north  of  Carbondale,  are  a  number  of  exi)Osures  of  clay  belonging 
to  the  lone  formation.  Attempts  have  been  made  at  various  times  to 
develop  these  deposits,  but  on  account  of  the  distance  from  railroad 
transportation  and  the  lack  of  large  exposures  of  uniformly  high-grade 
clay,  no  recent  commercial  production  has  been  attained.  Tiie  most 
l)romising  showings  are  in  Sec.  2,  T.  7  X.,  R.  8  E.,  :\I.  D.  :\1.,  on  the 
south  side  of  Cosumnes  River,  2  miles  east  of  Bridge  House.  Van 
Vleck  and  Sons  of  ^Michigan  Bar  own  the  north  half  of  the  section,  as 
well  as  large  acreages  to  the  south  and  ea.st,  some  of  which  may 
cover  deposits  of  future  value.  Geo.  Cutter  of  Sacramento  owns  the 
XEj  of  the  SE{  of  the  section;  C.  E.  Bundock  of  ^Michigan  Bar  owns 
the  S^  of  the  NW-^  of  the  SEj-  of  the  section.  The  ownership  of  the 
remaining  portions  of  the  section  was  not  determined. 

Portions  of  the  area  investigated  were  formerly  the  scene  of  hydraulic 
gold  mining  operations,  especially  near  the  eastern  .side  of  the  section, 
and  extending  over  i)arts  of  section  1.  Gravel  still  remains  over  por- 
tions of  the  area,  in  jilaces  to  a  dei)th  of  20  feet.  On  the  Geo.  Cutter 
pro])erty,  hydraulic  mining  has  ex])osed  a  bed  of  white  plastic  clay 
(sample  Xo.  143),  underlying  the  remnants  of  gravel  at  that  point. 
The  clay  bed  has  a  dip  of  7'  west,  following  the  slope  of  the  hill.  The 
total  expo.sed  thickness  of  clay  is  as  much  as  20  feet  in  ])laces,  l)ut  it 
was  not  possible  to  find  a  continuous  and  uniform  stratum  of  clay 
that  is  not  seriously  contaminated  with  a  network  of  hard,  weather- 
resisting  stringers  of  siliceous  limonite.  The  erosion  in  the  45  to  50 
years  since  hydraulic  mining  days  has  left  the  iron-bearing  stringers 
in  shar])  relief  on  the  ex])osed  clay  beds.  At  one  point,  near  the 
center  of  the  Cutter  property,  the  clay  is  not  greatly  contaminated 
over  an  area  about  50  feet  square,  and  for  a  thickness  of  three  to 
four  feet.  A  sample,  Xo.  148,  was  taken  from  this  exjiosure,  in  order 
to  indicate  the  ])Ossible  utility  of  clay  of  such  (piality,  if  it  could  be 
found  in  sufficient  abundance.     The  test  results  are  given  on  page  274. 

Just  north  of  the  Geo.  Cutter  property,  on  the  eastern  portion  of  the 
Van  Vleck  land,  a  stream  hnuk  affords  a  good  exposure  of  a  fine-grained, 
white-  to  cream-  and  but^'-burning  clay.  The  expo.sed  thickness  of  the 
bed  varies  from  :]  to  6  feet,  extends  for  200  feet  in  length,  and  can  be 
traced  in  cro.ss-gullies  for  at  least  100  feet  back  from  the  bank  of  the 
stream.     This  bed  apparently  underlies  the  clay  exposed  in  the  gravel 


186  DIVISION  OF  MINES  AND  MINING 

pits.     8am])le  No.  144  was  taken  for  te.stinf?,  the  resvilts  of  whicli  are 
•i'iveii  on  jiaye  27;}. 

It  is  entirely  possible  that  prosi)ect  drilling  over  this  area,  and  in 
adjoining  properties,  might  disclose  clay  dei)Osits  of  commercial  import- 
ance, but  in  view  of  the  minimum  truck  haul  of  6.5  miles  to  Carbondale, 
or  12  miles  to  the  Western  Pacific  Railroad  in  the  Sacramento  Valley, 
it  is  unlikely  that  serious  work  will  be  done  until  some  time  in  the 
future. 

Muddox  Pottery.  H.  C.  INIuddox  Company,  owner;  H.  C.  Muddox, 
president.    Office  and  plant  at  Thirtieth  and  L  streets,  Sacramento. 

This  company  operates  a  ]ilant  for  the  manufacture  of  sewer  pipe 
and  chimney  ware.  They  own  some  land  at  Carbondale,  Amador 
County,  where  they  dig  clay,  and  also  buy  some  common  clay  locally. 

Bibl:  State  Mineralogist's  Report  XXI,  p.  10. 

Natoma  Clay  Company.  This  company  was  organized  to  produce 
clay  from  the  settling  basins  that  have  resulted  from  gold  dredging 
operations  in  the  Natoma  dredging  area.  The  clay  consists  of  the  fine 
clay  and  silt  that  is  carried  by  the  reject  M'ater  from  the  dredge  ponds. 
This  water  is  passed  into  shallow  basins  which  were  previousl}-  formed 
by  the  dredge,  and  the  clay  and  silt  are  completely  settled  before  the 
water  is  returned  to  the  main  stream.  During  the  years  of  dredge 
operation  in  this  district,  many  millions  of  tons  of  clay  have  been 
artificially  produced  in  this  fashion.  The  individual  basins  are  trough- 
.shaped,  and  are  generally  less  than  30  feet  deep,  ranging  from  75  to  100 
feet  wide  at  the  surface.  The  sides  of  the  troughs  are  formed  by 
boulder  piles  on  an  angle  of  repose  of  approximately  45°,  or  by  vertical 
banks  of  unmined  gravel.  Some  of  the  basins  are  one  and  a  half 
miles  or  more  in  length.  Much  of  the  clay  area  has  been  prosi)ected 
by  hand-augers,  and  in  one  summer's  prospecting  alone,  over  6,500,000 
tons  were  proved. 

The  clay  is  extremely  fine  grained,  yet  contains  a  sufficient  proi)or- 
tion  of  non-plastic  matter  to  impart  desirable  ceramic  pro])erties  to 
the  mass.  The  proportion  of  non-plastic  matter,  and  the  fineness  of 
grain  varies  from  place  to  place,  but  in  any  given  basin  there  is  a 
remarkably  uniform  gradation  from  top  to  bottom,  with  the  finer 
material  nearer  the  surface,  making  it  possible  to  mine  two  or  three 
different  grades  of  material. 

Many  laboratory  and  full-scale  tests  have  been  made  on  the  clay, 
and  it  has  been  found  to  be  jiarticularly  useful  where  an  excellent 
range  of  dark-red  colors  and  a  fine  even  texture  is  desired.  High  dry 
.strength,  and  a  long  vitrification  range,  coupled  with  very  low  porosity 
when  vitrified,  have  been  thoroughly  demonstrated.  For  the  results 
of  tests  by  the  writer  on  two  different  samples,  see  No.  210  and  212, 
I)age  387."^ 

Mining  operations  were  started  in  the  summer  of  1926,  on  the  Alder 
(Jreek  pit,  half  a  mile  from  a  spur  track  of  the  Southern  Pacific  Co., 
and  one  and  a  half  miles  south  of  Natoma.  The  clay  is  mined  by  an 
Tnsley  10-ton  gasoline  shovel,  loading  into  contractor's  dump  cars 
on  a  narrow-gauge  track.  See  ])h()to  No.  55.  Haulage  to  llie  loading 
bins  at  the  siding  is  done  with  a  gasoline  locomotive. 

Bibl:  State  Mineralogist's  Report  XXI,  p.  3. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


187 


Panama  Pottery.  Owner,  Panama  Pottery  Company,  Inc.,  a  close 
corporation.  Victor  Axclson,  president ;  Andres  Anderson  and  Gustav 
fJohanson,  principal  owners.  Address,  post  office  box  797,  Sacramento. 
The  plant  is  jnst  sonth  of  Sacramento  city  limits  near  Twentj'-first 
Street  road.    See  photo  No.  56. 


Photo  No.  55.     Electric  shovel  in  preliminary  cut.     Natoma  Clay  Co.,  at  Natoma, 

Sacramento  County. 


Photo  No.  56.  Panama  Pottery  Company's  plant,  near  Twenty-first  Street  road, 
just  south  of  Sacramento.  (Fi-om  State  Mineralogist's  Report  XXI,  p.  8, 
1!(25.) 

This  company  owns  no  ehiy  deposits  at  ]iresent,  bnt  buys  red-burn- 
ino:  clay  locally  and  white  clay  from  Lincoln  and  lone.  The  products 
of  the  plant  are  houshold  stoneware,  including  jars,  water  coolers  and 
filters,  jugs,  mixing  bowls,  pitchers,  etc.     Fancy  garden  pottery  and 


188 


DIVISION   OF   MINES  AND  MINING 


common  and  fancy  flower  pots  are  also  produced.  Tlie  company  has 
patented  a  new  one-])iece  mold  for  embossed  flower  pots  and  are 
exclusive  makers  of  this  line  which  is  made  from  cream-burning  clays. 
See  photo  No.  57. 

Clay  for  the  various  products  is  crushed  in  a  dry  pan  and  elevated 
to  a  ;30-mesh  shalving  screen.  It  is  then  tempered  and  run  throuf»'h  the 
pug  mills,  aged  and  run  through  the  pug  mill  again.  After  molding, 
it  stands  for  a  short  time  on  shelves  and  is  taken  thence  to  the  dryer. 
White  ware  is  burned  48  to  52  hours  at  a  temperature  of  2200  degrees 
Fahrenheit,  and  red  ware  87  to  42  hours  at  a  temperature  of  1800 
degrees  Fahrenheit. 

Eciuipraent  at  the  plant  includes  two  pug  mills,  a  dry  i)an,  glaze 
grinder,  one  flower-])ot  machine,  three  jolly  wheels,  shaking  screen,  and 
two  down-draft  kilns  with  a  total  capacity  of  16,000  gallons  of  stone- 
ware.    Crude  oil  is  used  for  flriiig  the  kilns,  and  electricity  for  power. 


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Photo  No.   57.      Fancy  garden   pottery,   manufactured   by   Panama   Pottery   Com- 
pany, Sacramento.      (From  State  Mineralogist's  Report  XXI,  p.  8,  1925.) 

Sixteen  men  are  employed.  About  ten  days  are  required  for  a  com- 
plete run,  from  setting  to  the  time  of  drawing.  The  market  for  the 
goods  is  mostly  in  central  California  and  deliveries  are  nearly  all  by 
automobile  truck. 

Bibl:  State  IMineralogi.st's  Report  XXI,  ]).  7. 

Sacramento  Ilrivk  Compani)  (formerly  Biverside  Brick  Yard).  This 
is  a  .stock  comi)any,  subsidiary  to  Sacramento  Navigation  Com])any. 
W.  P.  Dwyer,  i)resident ;  A.  J.  Foster,  general  manager;  H.  K.  John- 
son, secretary.  JNIain  office,  Front  and  N  streets,  Sacramento.  The  brick 
plant  is  three  miles  south  of  the  Sacramento  city  limits,  near  Sacra- 
mento River. 

The  company  makes  common  brick  exclusively.  The  deposit  is  clay, 
sjind,  and  loam,  with  no  hnrdpan,  and  is  worked  about  16  feet  deep  by 


CLAY  RESOURCES  AND  CERA^flC  INDUSTRY  189 

51  steam  sliovel  and  draf^-liiio  scraper.  Clay  is  loaded  into  four-ton 
side  dump  ears  and  hauled  in  trains  by  dinkey  locomotives  to  the  plant, 
Avliere  it  is  (hnnpcd  into  I'olls.  elevated  to  the  pu^-  mill  and  temi)ered. 
It  passes  thence  to  a  soft-mud  hi'ick  machine  where  bricks  are  pressed 
and  dusted  with  ground  red  gro<r  from  an  outside  grog  grinder  and 
storage  bin.  From  the  brick  machine  the  bricks  ])ass  by  -wire  cableway 
to  steam-rack  dryers,  Avhere  they  are  dried  in  about  18  hours.  They 
are  then  burned  in  open-draft  field  kilns  for  seven  days  at  a  temperature 
of  1700°  to  1750°  P'ahrenheit.  The  kilns  contain  from  400,000  to 
500,000  bricks  each.  The  shrinkage  in  burning  is  about  6% .  The  plant 
has  a  daily  capacity  of  (JO. 000  bricks  and  em])Ioys  a  crew  of  sixty  men. 
Crude  oil  is  used  for  burning  bricks,  for  the  steam  .shovel  and  loco- 
motives, and  electric  i)Ower  is  used  for  oi)erating  machinery.  The 
direct  operation  of  the  brick  machine  retpiires  only  three  or  four  men. 
The  company  has  another  i)lant  between  the  present  site  of  operation 
and  the  river,  but  this  has  been  abandoned.  It  was  formerly  operated 
at  a  daily  capacity  of  125,000  bricks  during  the  dry  season  only,  but 
the  present  operations  are  carried  on  steadily. 

Bibl:  State  Mineralogist's  Reports  XV,  p.  403;  XXI,  p.  9. 

Valley  Brick  Compan!).  'Shun  office,  809  J  Street,  Sacramento.  Plant 
two  miles  southeast  of  Sacramento  city  limits,  near  S.  P.  and  Central 
California  Traction  Company  lines  to  Stockton.  H.  J.  McClatchy, 
lu-esident ;  A.  :\I.  Weston,  secretary ;  II.  F.  Goss,  plant  superintendent. 

The  proi)erty  includes  40  acres  of  clay  land  and  equipment  for  mak- 
ing common  red  brick.  The  deposit  has  an  average  depth  of  20  to  22 
feet,  of  which  the  upper  12  feet  is  yellowish-brown  clay  and  the  balance 
sandy  clay.  Near  the  surface,  and  covered  by  only  a  thin  layer  of 
loam,  occurs  about  two  feet  of  'hardpan,'  which  is  tight  and  difficult  to 
dig.  Clay  is  dug  with  an  Erie  shovel  and  loaded  on  cars  which  are 
hoisted  up  an  incline  to  the  grinding  Hoor.  After  grinding  the  clay  is 
.stored  in  a  bin.  Rolls,  previously  used  for  grinding,  are  being  replaced 
now  by  two  9-ft.  di-y  pans.  The  stiff'-mud  jirocess  is  used,  emi)loying  a 
Freise  auger  machine,  and  wire  cutter.  Green  brick  are  dried  six  to 
eight  days. 

Field  kilns  of  up-draft  tyi)e,  containing  about  180,000  brick  each  and 
using  for  fuel  crude  oil  which  has  been  atomized  by  air  under  80  pounds 
pressure,  have  been  in  use  heretofore.  Brick  was  water  smoked  for  three 
days  and  burned  three  days  thereafter,  reaching  a  maximum  tempera- 
ture of  1750°  during  the  latter  half  of  the  burning.  Eight  Funnan 
kilns,  with  a  cajiacity  of  600,000  brick  each,  will  be  built  soon,  and  the 
other  changes  will  increase  the  brick-making  cai)acity  from  42,000  to 
63,000  daily.  The  sea.son  for  digging  clay  and  making  brick  extends 
from  April  to  Xovembei-.  A  new  steam  plant  of  30()-li.]).  capacity  is 
being  built,  and  .steam  will  be  substituted  for  air  to  atomize  the  fuel  oil. 
During  the  busy  .season  30  men  are  employed. 

Bibl  (Clav  resources  of  Sacramento  County)  :  State  Min.  Bur. 
Bull.  38,  pp.  225-226  and  253;  Prel.  Rept.  7,  i).  91  ;  Rept.  XXI, 
pp.  2-10. 


190  DTVIRIOX  OP  MINES  AND  MINING 

SAN    BENITO  COUNTY. 
(By  C.  McK.  LiAizntE  and  W.  F.  Dietrich.)' 
General    Features. 

San  Benito  is  one  of  the  central  counties  situated  between  Monterey, 
a  coast  county,  which  adjoins  it  on  the  south  and  west,  and  ^Merced  and 
Fresno,  two  of  the  great  San  Joaquin  Valley  counties,  whieli  bound  it 
on  the  northeast.  Santa  Clara  County  and  a  corner  of  Santa  Cruz 
adjoin  it  on  the  north. 

The  county  extends  southeasterly  from  Pajaro  River  for  70  miles 
with  an  average  width  of  20  miles.  Its  area  is  1392  square  miles  and 
the  population,  most  of  whom  reside  in  or  near  the  few  towns  along  the 
railroad  in  the  northern  part,  is  8995   (1920  census). 

About  one-fourth  of  the  county  is  government  land.  Most  of  the 
remainder  was  long  held  in  the  form  of  large  land  grants  and  immense 
ranclios.  As  may  be  expected,  cattle-raising  early  became  an  important 
industry  and  it  still  is  of  prime  importance.  In  later  years  some  of 
these  ranchos  have  evolved  into  fruit  orchards  and  small  farms,  due  to 
irrigation  and  intensive  cultivation  of  the  valley  lands.  As  a  result, 
fruits  and  vegetables,  dairy  and  poultry  products,  as  well  as  hay,  grain, 
and  live  stock,  have  become  imi)ortant  sources  of  wealth.  ^Mining  has 
been  carried  on  since  1858,  the  total  recorded  mineral  production  to 
date  approximating  $30,000,000. 

Transportation  facilities  are  limited.  There  is  a  branch  of  the 
Southern  Pacific  railroad  from  Gilroy,  via  llollister,  the  county  seat, 
to  Tres  Pinos.  The  main  coast  line  of  the  Southern  Pacific  also  touches 
the  county  at  Logan,  after  passing  through  Pajaro  Gap.  The  '  Califor- 
nia Central,'  a  line  8  miles  in  length,  connects  the  Old  ^Mission  Port- 
land Cement  Company's  plant  with  the  Southern  Pacific  at  Chittenden. 
Other  parts  of  the  county  are  served  by  auto  stages  from  Holli.ster  and 
Tres  Pinos.  The  southern  section  can  be  reached  equally  as  Avell 
through  Coalinga  or  Mendota  on  the  San  Joaquin  Valley  side  or  from 
King  City  and  San  Lucas  on  the  west.  Excellent  highwaj^s  join  Hollis- 
ter  with  Merced  on  the  valley  highway  route  and  with  San  Juan  Bau- 
tista  on  the  coast  route  of  the  highway  system.  The  road  to  the  interior 
is  by  way  of  Paeheco  Pass. 

The  famous  Santa  Clara  Valley  penetrates  the  northern  end  of  the 
county  as  far  as  Hollister.  From  this  point  the  narrow  valley  of  San 
Benito  River  continues  southeasterly  to  the  southern  boundary.  This 
river  and  its  chief  tributary,  Tres  Pinos  Creek,  with  many  smaller 
streams  flowing  in  from  east  and  west  practically  drain  the  entire  area. 
Numerous  smaller  mountain  valleys  are  found  along  the  flanks  of  the 
two  ranges  of  the  Coast  system,  which  roughly  parallel  one  another  and 
dominate  the  topography. 

Geology. 

There  is  considerable  literature  on  the  geology  of  portions  of  San 
Benito  County,  but  most  of  the  detailed  geologic  studies  have  been 

'  Mr.  Laizure  studied  the  mineral  resources  of  this  county  in  1926.  See  State 
Mineralogist's  Report  XXII.  pp.  217-247.  His  general  description  of  the  county  and 
his  notes  on  the  clay  resources  were  revised  for  the  purposes  of  the  present  report  by 
Mr.  Dietrich,  who  visited  the  county  in  August,  1925,  and  made  an  unsuccessful 
attempt  to  find  some  of  the  deposits  of  high-grade  clay  that  had  been  previously 
reported.     Mr.   Dietrich  also  added   notes  on   the   deposit  at   Paicines. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  191 

confined  to  those  sections  considered  to  be  possible  oil-bearing  territory 
or  to  the  quicksilver  iiiininy:  districts,  and  no  single  geologic  report  fully 
cover.s  the  county. 

The  general  geology  as  shown  on  the  geologic  map  of  California  pub- 
lished by  the  «tate  Mining  Bureau  in  ll)l(i  is  briefly  outlined  in  the 
following  paragraphs. 

The  Gavilan  Range  on  the  western  side  is  composed  of  ancient  granitic 
rocks  associated  with  crystalline  schists  and  limestones.  Dolomite  and 
more  rarely  barite  deposits  occur  with  tlie  limestone  and  have  been 
developed  from  San  Juan  Bautista  southerly  to  Cienaga  Valley. 
Farther  south  in  a  snuUl  area  surrounding  the  Pinnacles  National 
Monument,  which  in  itself  is  an  example  of  intense  vulcanism,  fine- 
grained volcanic  rocks  occur.  In  the  southwestern  portion  of  the 
county,  from  To])o  Valley  south  and  east  to  iSan  Benito  lliver,  the 
formations  exposetl  are  sedimentary  rocks  of  Tertiary  age,  which  include 
numerous  gypsum  beds,  some  bituminous  sandstones  and  diatomaceous 
earth. 

On  the  northeastern  side  of  the  river  the  Diablo  Range  rises  abruptly, 
and  from  near  Hernandez  south  and  east  beyond  San  Carlos  Peak  it  is 
made  up  of  Franciscan  rocks,  chiefly  serpentine  but  with  much  red 
chert,  sandstone,  slate  and  schist  near  the  river.  From  Idria  north- 
westerly nearly  to  Llanada,  Cretaceous  and  Tertiary  rocks  make  up  the 
main  range.  From  Llanada  northward  to  the  northern  end  of  the 
county  the  Diablo  Range  is  typical  of  the  Coast  IMountains,  consisting 
of  serpentine,  chert,  metamorphic  sandstone,  slate  and  schist.  Quater- 
nary and  late  Tertiary  sediments  comprise  the  valley  area  surrounding 
Ilollister,  and  sandstone,  shales,  sands,  gravels  and  clays  are  much  in 
evidence  along  San  Benito  River  as  far  south  as  Hernandez. 

San  Andreas  fault,  a  dominant  structural  feature  of  the  geology, 
enters  the  county  near  Chittenden  and  runs  southeasterly  along  San 
Benito  River  as  far  as  the  town  of  San  Benito.  From  here  it  crosses 
a  low  divide  into  Rabbit  Valley,  and  from  there  it  follows  Bitterwater 
Creek  to  its  junction  with  Lewis  Creek  and  then  continues  southward 
up  Lewis  Creek. 

An  extensive  and  diversified  number  of  mineral  substances  are  found 
in  San  Benito  County.  Both  metallic  and  nonmetallic  minerals  are 
inckided  in  its  resources,  but  commercial  production  has  been  limited 
and  many  deposits  have  remained  entirely  undeveloped  on  account  of 
their  distance  from  railroad  transportation.  Neglect  of  mining  opjwr- 
tunities  may  also  be  due  in  part  to  the  fact  that  many  deposits  are  on 
l^rivate  lands,  whose  owners  are  interested  in  other  lines  of  activity. 

Quicksilver  production  has  given  San  Benito  its  reputation  in  the 
mining  world,  as  it  ranks  among  the  oldest  and  most  important  quick- 
silver producing  counties.  The  New  Idria  mine,  in  the  southern  part, 
is  the  largest  single  producer  of  quicksilver  in  the  state.  Since  1918, 
however,  the  value  of  the  county's  annual  output  of  quicksilver  has 
been  exceeded  by  that  of  cement.  Crushed  rock  production  closely 
follows  quicksilver  in  annual  value  of  output.  Other  mineral  products 
which  have  been  produced  in  greater  or  lesser  amounts  are :  antimony, 
asbestos,  asphalt,  bituminous  rock,  brick,  chroraite,  coal,  dolomite,  gems, 
gypsum,  lime  and  limestone,  magnesite,  manganese,  and  mineral  water. 

Barite.  clay,  copper,  diatomaceous  earth,  feldspar,  gold,  iron,  mont- 
morillonite,  petroleum,  strontium,  and  volcanic  ash  also  occur  here, 


192  DIVISION  OP   MINES  AND   MINING 

but  the  commercial  value  of  tliese  dejwsits  is  not  as  yet  established 
A  number  of  other  mineral  spec-its  are  represented  in  the  county,  but 
llieir  occurrence  is  of  mineraloy:ical  interest  only. 

Clay    Resources. 

There  have  been  a  number  of  reported  occurrences  of  high-grade 
clay  in  the  county,  but  none  of  these  have  been  of  sufficient  economic 
interest,  in  view  of  the  comi)arative  isolation  of  the  county  from  indus- 
trial centers,  and  the  lack  of  cheap  transportation  from  the  reported 
occurrences,  to  warrant  serious  investigation. 

The  larger  valleys  of  San  Benito  Kiver  and  its  tributaries  contain 
ample  supplies  of  common  clay  suitable  for  the  manufacture  of  heavy 
structural  ware.  The  Paicines  deposit,  described  herein,  is  typical  ot 
these.  There  has  been  no  commercial  output  of  clays,  as  such,  in  the 
county,  and  the  only  clay  material  being  utilized  at  the  present  time 
(19'2(i)  is  that  mined  by  the  Old  ^Mission  Portland  Cement  Company  for 
the  manufacture  of  cement  at  their  plant  at  San  Juan  Bautista. 

Abbe  Ranch.  There  is  a  deposit  of  clay  containing  considerable 
sandy  material  on  the  C.  H.  Abbe  Ranch,  12  miles  south  of  Paicines 
on  the  Idria  road.  This  clay  fuses  at  a  rather  low  temj^erature.  but 
does  not  crack  or  swell.  It  appears  to  be  an  impure  montmorillonite. 
The  bed  stands  i)ractically  vertical  and  cuts  across  a  ridge  from  top  to 
bottom. 

A  white  kaolinized  rock  that  slowly  breaks  down  in  water,  forming  a 
slightly  plastic  clay  with  a  comparatively  low  fusing  point,  is  exposed 
in  a  cut  along  the  San  Benito  road  about  IS  miles  south  of  Tres  Pinos. 
This  variety  of  clay  could  probably  be  utilized  in  the  ceramic  indus- 
tries.    It  is  undeveloped. 

The  Alpine  Quicksilver  Mining  Company  in  1915  burned  about  260,- 
000  brick  in  field  kilns  on  lower  Clear  Creek  near  Hernandez  for  use 
in  building  their  reduction  furnace.  The  clay  was  dug  locally.  Some 
of  these  brick  still  remain  along  the  road  and  appear  to  be  of  good 
quality. 

W.  T.  Maeder,  554  Sixty-sixth  Street,  Oakland,  California,  has  sub- 
mitted a  sample  of  siliceous  clay,  jiossibly  a  fireclay,  from  the  Bitter- 
water  section.     Undeveloped. 

M.  A.  Martin,  formerly  of  Ilollister.  located  some  clay  which  burns 
white,  or  nearlv  wliite.  near  tlie  head  of  Willow  Creek  in  T.  15 
S.,  R.  6  E.  ■ 

Dr.  J.  M.  O'Donnell  of  Ilollister  owns  a  deposit  along  Bird  Creek, 
three  miles  south  of  Ilollister.  The  bed  is  exposed  for  a  considerable 
depth  in  several  of  the  gulches,  and  a  well  was  sunk  80  feet  without 
reaching  the  underlying  rock.  The  clay  is  light  grey  in  color,  very 
plastic  and  without  grit.  It  burns  to  a  cherry  red  and  is  said  to  be 
suitable  for  pottery  use. 

Paicines  Clay  Deposit.  In  Sec.  36,  T.  12  S.,  R.  6  E.,  M.  D.  M.,  0.3 
mile  south  of  Paicines  on  the  San  Benito  road  is  an  exposure  of  yellow 
plastic  clay  of  ]n-obable  Pliocene  age.  A  road  cut  at  this  point  exposes 
a  bank  6  feet  high,  but  the  deposit  is  probably  at  least  20  feet  thick, 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  193 

and  covers  an  area  of  many  acres,  with  little  or  no  ovei-burden.   Similar 
deposits  occur  in  various  other  localities  in  the  San  Benito  Valley. 
See  sample  No.  118,  page  341. 

H.  y.  Vndi  rwood  of  Ilollister  has  submitted  samples  of  plastic  clay 
of  fairly-high  alumina  content  found  at  several  points  in  the  county. 

Bibl    (On   San  Benito  Count v  clav  resources)  :  State  Min.  Bur. 
Bull.  38,  p.  226;  Prel.  Kept'.  7,  p".  91;  Kept.  XXII,  pp.  228-229. 

SAN    BERNARDINO  COUNTY. 
General    Features. 

San  Bernardino,  with  an  area  of  20,157  square  miles,  is  by  far  the 
largest  county  in  the  state.  It  is  bounded  on  the  north  by  Inyo  County, 
on  the  east  by  the  states  of  Nevada  and  Arizona,  on  the  south  by 
Riverside  County,  and  on  the  west  by  Los  Angeles  and  Kern  counties. 
The  population  IS  73,401  (1920  census). 

The  topography  of  the  county  consists  largely  of  mountains  and 
desert,  and  is  characteristic  of  the  Great  Basin,  which  has  been 
described  by  many  geologists.  The  famous  Mojave  Desert  is  almost 
wholly  confined  within  the  limits  of  the  county,  but  extends  southward 
into  Riverside  County.  ^lost  points  in  the  county  can  be  reached  witli 
comparative  ease  by  railroad  or  highway. 

The  geology  of  the  entire  county  has  never  been  studied  in  detail,  but 
many  interesting  reports  have  been  made  by  various  members  of  the 
r.  S.  Geological  Survey,  and  others,  on  different  areas  in  the  county. 
A  large  i)art  of  the  county  is  covered  by  Tertiary  and  Quaternary  vol- 
canics,  and  Quaternary  gravels,  but  many  other  formations  are  present, 
particularly  in  the  numerous  mountain  ranges.  Chief  among  these 
are  i)re-Cambrian  and  Paleozoic  metamorphics,  and  various  Tertiary 
formations,  principally  ^Miocene. 

The  mineral  resources  are  varied,  and  the  aggregate  production 
places  the  county  in  fifth  place  (1926)  among  the  counties  of  the  state 
in  the  value  of  its  mineral  products.  Cement  is  the  most  important 
product,  and  there  are  three  plants  in  the  county.  Other  mineral 
products  are  borates,  calcium  chloride,  clay,  copper,  fuller's  earth,  gold, 
lead,  lime,  limestone,  mineral  water,  petroleum,  pota.sh,  salt,  silver, 
soda,  miscellaneous  stone,  talc,  and  tungsten  concentrates.  Occur- 
rences of  a.sbestos,  barytes,  gems,  granite,  gypsum,  iron,  manganese, 
marble,  mineral  paint,  nitre,  soapstone,  strontium,  vanadium,  and  zinc 
are  known. 

Clay   Resources. 

Deposits  of  high-grade  clay  occur  at  a  number  of  localities  in  the 
county.  Two  or  three  of  these  have  been  developed.  The  most  inter- 
esting deposits  are  those  in  the  Hart  :\Iountains,  described  below  under 
H.  F.  Coors  and  Standard  Sanitary  Manufacturing  Company.  A 
plastic  kaolin  of  exceptional  quality  has  been  developed  on  these  prop- 
erties. It  is  likely  that  more  intensive  prospecting  will  disclo.se  hitherto 
unknown  deposits  of  a  similar  type. 

Common  clays  are  sufficiently  abundant  in  the  vicinity  of  San  Ber- 
nardino to  serve  all  purposes,  and  the  apparent  lack  of  suitable  deposits 

13 — 5+979 


194 


DIVISION  OF  MINES  AND  MINING 


elsewhere  in  the  eoiiiity  is  of  no  importance,  because  of  the  fact  that 
these  areas  can  never  be  expected  to  snjjport  a  larj^e  popiUation. 

Two  ceramic  materials  of  special  intei-est  occur  in  San  IJernardino 
County,  convenient  to  railroad  trans|)ortatiou.  These  are  ganister 
and  talc  schist.  A  large  ganister  deposit  is  beinu'  Avorked  bv  the  Atlas 
Fire  Brick  Company  of  Los  Angeles  in  Sec.  IM,  T.  9  N.,  R.  3  W.,  four 
miles  from  Hicks  Station  on  the  Santa  Fe  railroad,  betAveen  Victorville 
and  Barstow.  It  is  the  equivalent  of  Pennsylvania  ganister  in  the 
manufacture  of  silica  brick.  The  talc  schist  occurs  in  Sec.  29,  T.  19  N., 
R.  4  E.,  13  miles  northeast  of  Newberry  Station  on  the  Santa  Fe  rail- 
road. It  is  being  mined  by  John  J.  Kennedy  of  Daggett,  and  is  in 
use  as  an  ingredient  of  white  tile  bodies  in  a  few  Los  Angeles  plants. 

H.  F.  Coors  Deposit.  Owned  by  H.  F.  Coors,  Inglewood.  The  i)rop- 
ertv  consists  of  7^  unpatented  mineral  claims  in  the  old  mining  town  of 
Hart.     The  claims  cover  parts  of  Sees.  13  and  24,  T.  14  N.,  R.  17  E., 


Photo  No.   58.     H.  F.  Coors  Kaolin  Deposit,  Hart,  San  Bernardino  County. 

(Sample  No.  57.) 


S.  B.  M.  The  clay  is  a  white-burning  ball  clay,  possessing  the  properties 
of  a  mixture  of  china  clay  and  ball  clay.  It  occurs  as  an  alteration  of 
an  eruptive  rock  relatively  high  in  alumina  and  low  in  alkalis  and  iron. 

At  the  time  of  visit,  in  June,  1925,  the  property  was  idle,  but  enough 
development  work  had  been  done  in  two  different  places,  one  of  which  is 
shown  in  photo  No.  58,  to  demonstrate  the  presence  of  an  extensive 
deposit  of  uniform  material.  The  trench  shown  in  the  photo  was  150 
feet  long,  8  feet  deep,  and  15  feet  wide.  Ten  to  fifteen  feet  vertically 
below  the  bottom  of  the  trench,  a  lOO-ft  tunnel  had  been  driven.  At 
another  point  on  the  property,  about  200  yards  to  the  southeast,  a  65-ft. 
tunnel,  originally  driven  in  the  search  for  gold,  had  been  enlarged  at 
the  face  into  a  room  20  by  12  feet  in  section,  by  8  feet  high,  exposing 
similar  material  to  that  present  in  the  cut. 

Since  1926  Mr.  Coors  has  been  mining  from  the  deposit  to  secure 
clay  for  his  plant  in  Inglewood  (see  under  Los  Angeles  County). 


CLAY  RESOURCES  AND  CERAMIC  INDTTSTRY  195 

Sample  No.  57  Avas  takon  for  tostiiij;,  the  results  of  whieli  are  on 
liajze  264. 

(}Ja<ldi)ig,  McTiran  <in<l  Conrpnin/.  Ofifice  of  Southern  Division  at  621 
S.  Hope  Street,  Los  Anproles.  This  eompany  owns  a  dejiosit  of  bnff- 
hurnins:  clay,  4.2  miles  by  road  noi'tlieast  of  Bryman,  a  station  on  the 
Santa  Fe  railroad  between  Victorville  and  Barstow.  The  clay  is  mined 
from  an  open  cut,  which  at  the  time  of  visit,  in  June,  1925,  was  40  feet 
wide  and  100  feet  lon<>'.  The  bank  was  40  feet  hip'h  at  the  face  of  the 
pit.  Pi"oni  100  to  150  tons  per  year  were  beinp;  mined  and  shipped  to 
Los  Anofeles  for  use  in  the  manufacture  of  face  brick. 

Sample  No.  55  was  taken  for  testin<r.     The  results  are  on  paue  314. 

7?.  H.  HolJiman  and  D.  Murphy  have  located  12  mineral  claims  cover- 
infr  extensive  outcrops  of  clay  beds  in  Sec.  14,  T.  12  N.,  R.  14  E., 
S.  B.  ]\r.,  on  the  western  slope  of  the  ]\fid  Hills,  which  connect  the 
Providence  ^fountains  on  the  southwest  with  the  New  York  ]\[ountains 
to  the  northeast.  By  the  existing  road,  the  deposit  is  13  miles  southeast 
of  Cima,  but  a  road  with  easy  down-grade  could  be  built  fi-om  the 
deposit  to  the  Los  Angeles  and  Salt  Lake  Railroad  line  south  of  Tima. 
This  road  would  be  from  six  to  seven  miles  in  length. 

On  the  area  covered  hj  the  claims  there  are  three  distinct  beds  of 
white  semi-plastic  clay,  each  of  which  is  from  six  to  fifteen  feet  thick 
and  can  be  traced  intermittently  for  some  2000  feet  on  the  strike. 

The  clay  shows  the  general  characteristics  of  an  impure  kaolin,  and 
is  evidently  derived  from  a  highly  feldsj^athic  granite  that  is  abundant 
in  this  locality.  The  (puility  of  the  clay  as  exposed  on  the  surface  and 
in  the  shallow  Avorkings  is  widely  variable  and  it  is  likely  that  consider- 
able development  work  will  be  needed  in  order  to  prove  the  existence 
of  sufficiently  large  bodies  of  material  of  uniform  quality  to  warrant 
commercial  ])roduction . 

Development:  The  deA^elopment  work  consists,  in  ]iart,  of  a  shaft 
ten  feet  deep  from  the  bottom  of  -which  ten  feet  of  drifting  has  been 
done.  The  clay  bed  at  this  point  is  steeply  tilted  and  the  attempt  was 
made  to  cut  it  by  a  12()-foot  tunnel  25  feet  below  the  outcrop,  but  so 
far  as  the  work  had  progressed  at  the  time  of  visit  on  June  18,  1925, 
the  material  encountered  in  the  tunnel  was  inferior  in  quality  to  that 
exposed  nearer  to  the  surface. 

The  other  tAvo  clay  beds  lie  higher  up  on  the  mountain,  and  no 
development  has  been  done.     The  upi)er  beds  lie  nearly  horizontal. 

The  geology  is  somewhat  complex  in  this  area.  There  are  a  number 
of  rhyolitic  flow^s,  as  well  as  a  few  remnants  of  sedimentary  formations, 
princii)ally  sandstone  and  limestone. 

Sample  No.  46  was  taken  for  testing.     The  results  are  on  page  349. 

MiUei  Clay  Deposit.  An  extensive,  but  undeveloped  deposit  of  clay 
occurs  near  the  southern  boundarv  of  the  Avest  half  of  Sec.  31,  T.  9  N., 
R.  3  W.,  S.  B.  M.,  OAvned  by  M.  J. 'Millet  and  J.  J.  Kennedy  of  Daggett. 
The  claA'  is  exposed  on  the  surface  one-third  of  a  mile  south  of  a  ganister 
deposit  that  is  OAA^ned  by  the  Atlas  Fire  Brick  Company  of  Los  Angeles. 
Several  shalloAv  i)its  and  short  tunnels  liaA'e  been  excaA^ated,  giving 
indications  of  a  clay  bed  10  to  20  feet  thick  and  extending  discontinu- 
ously  for  a  distance  of  nearly  one-half  mile,  Avith  an  east-west  strike. 


196 


DIVISION  OP  MIXES  AND  MININO 


It  is  impossible  to  estimate  from  the  present  state  of  development  the 
l)robable  tonnage  and  uniformity  of  the  occurrence.  !Sami)le  Xo.  53 
was  taken  for  test,  and  the  results  ^iven  on  pa<;e  2S8  are  sufficiently 
encouraging  to  Avarrant  further  investigation.  The  sample  was  taken 
from  a  shallow  exposure  made  in  a  small  cut,  and  it  is  not  unlikely 


Photo  No.  59.     Pacific  Kaolin  Mine.     Standard  Sanitary  Co. 
Upper   worlvings.       (Sample   No.    45.) 

that  it  shows  more  contamination  with  surface  debris  than  would  be 
found  at  points  further  beneath  the  present  surface. 

Standard  Sanitary  Companij.     One-half  mile  south  of  the  old  gold- 
mining  town  of  Hart,  the  Standard  Sanitary  Company  owns  a  deposit 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


197 


of  \vliite-burniii<i-   hiill    chiy    that    is   bciim    exploited   by   unclerground 
nietbods. 

Tbe  clay  is  the  residt  of  altoi-ation  of  a  foldspathie  ip'iieotis  rock,  the 
original  nature  of  ■which  was  not  determined.  The  enclosing  and  over- 
lying rocks  are  rhyolite.  The  total  extent  of  the  deposit  is  unknown, 
but  the  height  is  from  60  to  70  feet,  the  width  at  least  50  feet,  and  the 
length  over  200  feet,  as  exposed  on  tlie  sui'face  and  in  the  workings. 
The  dimensions  given  probably  represent  but  a  small  proportion  of  the 
total  material  available. 

Development  and  Mininc;  :  The  development  work  consists  of  two 
sets  of  workings.  The  upper  workings,  now  abandoned,  lie  up  the 
slope  of  the  hill  some  80  feet  vertically  above  the  present  tunnel  level. 
The  upper  workings  consist  of  an  open  cut  extending  into  several 
underground  chambers  from  which  clay  has  been  mined.  See  photo 
No.  59. 


Photo  No.  60.     Pacific  Kaolin  Miiio.     Standard  Sanitary  Co.     Trestle  and  bin  on 
lower  tunnel  level.   (Sample  No.  4  4  taken  from  face  of  stope.) 

The  lower  tunnel  was  driven  in  order  to  provide  better  facilities  for 
breaking  and  loading  the  clay,  and  to  permit  more  systematic  mining. 
At  the  time  of  visit  on  June  17,  1925,  this  tunnel  had  been  driven  150 
feet  in  length  and  shortly  after  entering  the  hill,  it  had  been  gradually 
enlarged  to  a  chamber  which  at  the  face  was  ;^0  x  30  feet  in  section. 

The  clay  requires  liglit  bla.sting  but  is  sufficiently  soft  so  that  hand 
augers  can  be  used  for  most  of  the  drilling,  with  the  aid  of  hand- 
hammer  drilling  in  the  harder  portions.  The  broken  material  is  hand- 
loaded  into  mine  cars  and  hand-trammed  to  the  loading  bins  outside 
of  the  portal  of  the  tunnel.  See  ])hoto  No.  60.  A  motor  truck  is  used  for 
hauling  to  Ivanpah,  a  distance  of  15  miles  over  a  rough  road,  but  one 
that  has  a  uniform  down-grade  in  favor  of  the  load. 

At  the  time  of  visit,  four  men  were  working,  including  the  foreman 
and  the  truck  driver.  The  i^roduetion  varies  from  15  to  20  tons  per 
day. 


198  DIVISION  OP  MINES  AND  MINING 

This  propertj'  is  worked  for  three  or  four  months  of  the  year. 
During  the  idle  period  the  same  crew  is  employed  at  the  company's 
feldspar  property'  near  Campo,  San  Diego  Count}'. 

Samples  No.  44  and  45  were  taken  for  testing.  The  results  are  given 
on  page  264. 

Bibl  (Clay  resources  of  San  Bernardino  County)  :  Cal.  State 
Min.  Bur.  Bull.  38,  pp.  226-227,  253-254;  Prel.  Kept.  7,  pp. 
92-93 ;  Kept.  XV,  pp.  860-862.  The  most  important  references 
on  the  geology  of  the  county  are :  Darton,  N.  H.,  et  al..  Guide 
Book  of  the  Western  U.  S.,  Part  C,  U.  S.  G.  S.  Bull.  613 ;  Ball, 
Sidney  II.,  Geologic  Reconnaissance  of  Southwestern  Nevada 
and  Eastern  California,  U.  S.  G.  S.  Bull.  308. 

SAN    DIEGO   COUNTY. 
General    Features.* 

San  Diego  was  discovered  in  September,  1542,  by  Juan  Rodriguez 
Cabrillo.  This  discovery  of  the  San  Diego  region  by  Cabrillo  was  fol- 
lowed by  the  establisliment  of  tlie  first  Franciscan  ^Mission  in  California 
on  June  16,  1769,  by  Padre  Junipero  Serra.  The  location  of  tliis 
mission  at  San  Diego  led  to  tlie  early  settlement  of  the  Pacific  coast 
and  is  of  special  prominence  in  the  early  history  of  California. 

The  principal  industries  are  agriculture,  stock  raising,  dairying,  and 
commercial  fisheries.  The  mining  industry  is  relatively  undeveloped, 
although  the  mineral  resources  of  the  county  are  varied  and  extensive. 
Tlie  rapid  and  continued  growth  of  the  city  of  San  Diego  and  the  manu- 
facturing industries  on  tlie  Pacific  coast  have  led  to  the  development 
of  deposits  of  structural  and  industrial  materials  throughout  the 
county. 

San  Diego  is  bouiuled  on  the  east  by  Imperial  County,  north  by 
River.side  and  Orange  counties,  west  by  the  Pacific  Ocean,  and  south  by 
Mexico.  Its  area  is  4221  square  miles  and  its  population  112,248 
(census  of  1920). 

The  countv  and  the  citv  of  San  Diego  are  served  bv  two  railroads, 
the  Santa  Fe  and  the  San  Diego  and  Arizona.  The  Santa  Fe  railroad 
enters  the  county  at  San  Onofre  and  follows  the  coast  line  to  San  Diego, 
connecting  the  lattter  with  the  city  of  Los  Angeles.  From  the  main 
trunk  line  there  is  a  branch  line  from  Los  Angeles  Junction,  known  as 
the  Fallbrook  branch,  that  runs  as  far  as  Fallbrook ;  another  branch 
line  runs  from  Oceanside  to  Escondido,  giving  railroad  transportation 
to  an  important  citrus  belt.  The  San  Diego  and  Arizona  railroad  runs 
along  the  border  of  ^Mexico  and  the  county,  connecting  San  Diego  with 
Imperial  Valley  at  El  Centre.  The  Cuyamaca  branch  of  this  line  runs 
from  San  Diego  to  Lakeside,  affording  transportation  for  El  Cajon 
Valley  and  other  interior  points.  From  the  port  of  San  Diego  regular 
steamer  lines  plv  between  San  Diego,  Los  Angeles,  San  Francisco, 
Seattle. 

San  Diego  has  a  wonderful  system  of  highways  and  good  roads  which 
give  access  to  all  parts  of  the  county.  Two  main  paved  highways  from 
Los  Angeles  to  San  Diego  parallel  the  coast.  The  coast  route  follows 
the  coast  line,  and  the  inland  route  is  via  Riverside,  Fallbrook  and 

•  This  and  the  subsequent  paragraphs  on  geoloRv  are  abstracted  from  a  recent 
report  by  W.  Burling  Tucker,  State  Mineralogist's  Kept.  XXI,  pp.  325-327,   1925.. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  199 

Escondido  to  San  Diego.  Two  paved  liiglnvays  eoniieet  Imperial  Valley 
with  San  Dieyo.  Five  scenic  higliways,  stretching  out  from  San  Diego 
like  ribs  of  a  huge  fan  with  its  northern  tip  at  Oceanside  and  its  south- 
ern tip  at  Campo,  within  one  mile  of  the  Mexican  border,  atford  easy 
access  by  automobile  to  all  parts  of  the  San  Diego  Mountains.  Each 
one  of  these  intersects  the  road,  forming  the  outer  rim  of  the  fan,  which 
traverses  practically  the  entire  Incopah  Range  from  northeast  to  south- 
west, a  distance  of  more  than  170  miles.  The  total  mileage  of  all  the 
fan-shaped  routes  is  nearly  600  miles. 

The  to])ographic  features  of  the  count}'  consist  of  a  series  of  parallel 
ranges  of  granite,  witli  a  southeast  trend,  including  the  soutlieastern 
continuation  of  the  San  Jacinto  Range  of  Riverside  County.  Among 
these  granite  ranges  are  valleys  occupied  by  ])arallel  belts  of  meta- 
morphic  rock,  chiefly  slate  and  mica  schist,  witli  some  quartzite  and 
lentils  of  limestone.  These  have  a  general  northwest  strike,  Avith  steep 
dips  to  the  east,  and  extend  from  Mexico  into  Riverside  and  Orange 
counties.  The  Cuyamaca  and  Laguna  Mountain  ranges  extend  north- 
west and  southeast,  and  are  over  5000  feet  high  at  many  i)oints.  Cuya- 
maca Peak  has  an  elevation  of  6515  feet,  and  Laguna  Mountain  an 
elevation  of  6500  feet.  These  are  intrusions  of  diorite  and  gabbro 
Avliich  occur  at  intervals  in  the  granite  area.  Southwesterly  from  this 
elevated  belt  the  altitudes  decline  toward  the  coast.  West  of  the  granite 
area  is  a  belt  of  volcanic  felsite  and  tuff  that  extends  northwest  some 
40  miles  from  the  Mexican  line.  The  belt  is  only  a  few  miles  wide,  for 
the  most  part  being  buried  beneath  mesa  formations.  It  is  exposed  at 
many  points,  forming  the  peaks  of  Otay,  San  Miguel,  and  Black  Moun- 
tains. The  mesas  of  Tertiary  deposits  which  occur  on  the  west  flank 
of  the  crystalline  formations  gently  slope  seaward,  from  an  altitude  of 
about  500  feet  at  its  eastern  margin  to  an  elevation  of  about  300  feet 
near  the  coast  line.  From  the  main  divide  the  surface  slopes  steeply 
eastward  towai-d  the  Salton  Basin. 

The  principal  valleys  of  the  county  are  those  occupied  by  the  Santa 
Margarita,  San  Luis  Rey,  San  Dieguito,  San  Diego,  Sweetwater,  Otay, 
and  Tia  Juana  rivers.  They  are  characterized  by  wide,  flat,  gently- 
sloping  floors,  bordered  by  steep  slopes  or  bluffs  several  hundred  feet 
high,  and  they  contain  streams  that  rise  far  back  in  the  mountain  area. 
All  these  streams  flow  to  the  ocean.  El  Cajon  Valley,  Santa  Maria 
Valley,  and  Warner  Valley  are  comparatively  flat  tracts,  some  of  them 
surrounded  by  steep  mountain  walls,  and  cover  many  square  miles, 
within  the  highland  area,  and  form  the  broad  valleys. 

Geology. 

The  geolog;v'  of  San  Diego  County  has  been  described  in  detail  by  W. 
A.  Goodvear  in  the  Eighth  Annual  Report  of  the  State  Mineralogist, 
pp.  516-628,  for  the  year  1888  ;  by  Harold  W.  Fairbanks  in  the  Eleventh 
Report,  pp.  76-120,  for  the  year  1892 ;  by  Dr.  F.  J.  II.  IMerrill  in  the 
Fourteenth  Report  of  the  State  Mineralogist,  pp.  637-6-45,  for  the  vears 
1913  and  1914 ;  in  Water  Supply  Paper  No.  446,  U.  S.  Geological"  Sur- 
vey, 'Geology  and  Ground  Waters  of  the  Western  Part  of  San  Diego 
County. ' 

The  formations  of  San  Diego  County  are  granites  and  other  igneous 
crystalline  rocks,   of  several   ages,   metamorphic   strata   of   great   age. 


200  DIVISION  OF  MIXES  AND  MINING 

possibly  Carboniferous  or  older,  and  sandstone,  shales,  conglomerates, 
sands,  gravel,  and  clays  of  ^Mesozoic  and  Tertiary  age. 

The  granites  upon  Mhieh  the  metamorphic  rocks  rest,  and  by  which 
they  are  intruded,  are  of  .several  types.  These  gi-anites  are  in  turn 
intruded  here  and  there  by  basic  rocks  of  the  diorite  and  gabbro  types. 
The  latter  are  cut  at  many  points  by  pegmatite  dikes,  which  also  appear 
as  intrusives  in  the  schists  and  in  the  granites.  Two  area.s  of  these 
basic  intrusives  form  substantial  mountain  ranges,  one  traversing  the 
Cuyamaca  Grant  from  north  to  south,  and  forming  three  peaks,  of 
which  the  sonthermost,  6515  feet  high,  is  known  as  ]\Iount  Cuyamaca. 
Ten  miles  southea.st  is  a  diorite  ridge,  known  as  Laguna  ^Mountain,  of 
which  the  summit  attains  an  altitude  of  over  6500  feet. 

On  the  southwest  flank  of  the  granite  area  is  a  volcanic  flow,  a  few 
miles  wide,  extending  northwest  some  40  miles  from  the  Mexican 
boundary.  This  area  is  largely  overlain  by  Tertiary  formations.  The 
])rincipal  rocks  exposed  are  felsite,  tuffs,  and  volcanic  conglomerates. 
The  metamorphic  formations  are  mica  schi.sts.  slates,  quartzites.  and 
limestone ;  the  mica  schists  are  well  exposed  at  Julian  and  on  the  west 
flank  of  the  Laguna  range  of  mountains.  The  Cretaceous  strata 
exposed  in  this  region  are  of  the  Chico  series  and  appear  in  the  bluffs 
on  Point  Loma  and  at  La  Jolla.  as  described  by  Harold  W.  Fairbanks 
in  the  Eleventh  Report  of  the  State  ^Mineralogist,  p.  95. 

The  earlier  Tertiary  or  Eocene  depasits  appear  at  the  surface  from 
Los  Penasquitos  Canyon  northward  to  Buena  Yista  Creek;  the  later 
Tertiary  deposits  are  exposed  from  Los  Penasquitos  Canyon  southward 
to  the  ]\Iexican  boundary,  and  from  Buena  Vista  Creek  northward  to 
the  north  boundary  of  the  county.  The  earlier  Tertiary  or  Eocene 
beds  are  made  up  of  white  sandstone,  underlain  by  alternating  layers 
of  shale,  sandstone,  and  thin  layers  of  clay  and  shale,  limestone  and 
sand.stone,  and  marl  and  calcareous  material. 

The  principal  mineral  products  of  San  Diego  County  are  miscel- 
laneous stone,  feldspar,  brick  and  hollow  building  tile,  granite,  and 
pottery  clay.  Other  minerals  that  have  been  produced  in  recent  years 
are  mineral  water,  gems,  gold,  silver,  fuller's  earth  (Otaylite').  lime, 
magnesium  chloride,  salt,  and  silica.  Occurrences  of  bismuth,  lithia, 
marble,  nickel,  soapstone,  and  tin  are  known.  Potash  has  been  pro- 
duced from  kelp. 

Clay   Resources. 

Important  commercial  deposits  of  fireclay  and  pottery  clay,  mainly 
of  Eocene  and  Pleistocene  age.  occur  in  northern  San  Diego  County,  in 
the  vicinity  of  Carlsbad  and  Cardiff.  Some  of  the  fireclays  are  similar 
to  the  famous  Gros-Almerode  clays  of  Germany.  On  the  top  of  El 
Cajon  ]\Iountain.  in  the  southern  part  of  the  county,  is  an  interesting 
deposit  of  residual  kaolin.  Avhich  was  worked  for  a  short  time,  but  has 
little  commercial  value  on  account  of  its  inaccessibility.  It  serves  as  a 
valuable  guide  to  further  prospecting  in  the  region. 

Red-burning  .shales  suitable  for  the  manufacture  of  common  brick, 
paving  brick,  and  hollow  tile  are  reasonably  abundant  in  the  vicinity  of 
San  Diego,  but  softer  clays  that  can  be  used  without  grinding  are  not 
plentiful  in  locations  close  to  the  center  of  consumption  (principally 
the  city  of  San  Diego).      Deposits  of  Miocene  Tertiary  clays  on  the 


(LAY  KESOl'HCKS  AND  CEKAMK'  INDUSTRY  201 

eastern  marjrin  of  the  county  were  noted  in  an  earlier  report/  Tliese 
are  as  yet  commercially  inaccessible,  and  but  little  is  known  of  their 
properties. 

The  feldspar  and  ({uartz  deposits  of  San  Diciro  County  are  of  par- 
ticular interest  to  the  clay-workin<;  industry.  The  greater  part  of  the 
feldspar  used  in  California  is  produced  at  Camjio. 

Cdlifoniia  Clay  Produrts  Companji  and  Mission  China  Compayv/. 
Victor  Kremer,  president.  Offices,  315  Western  Mutual  Life  Building, 
Los  Angeh^s.  The.se  eom])anies  own  a  fireclay  property  in  Sec.  4,  T. 
13  S.,  R.  3  W.,  S.  B.  M.,  8  miles  by  road  in  a  northeasterly  direction 
from  C'arditf.  and  two  miles  northeast  of  the  property  of  Gladding, 
McBean  and  Company  ((/.v.). 

The  holdiiigs  of  the  California  Clay  Products  Company  consi.st  of 
the  Pearl  and  the  Dorothy  Ann  placer  claims,  comprising  20  acres  each ; 
and  the  ]\Ii.ssion  China  Company  owns  tAvo  adjoining  claims  known  as 
the  Robert  Charles  and  the  Thomas  Hewitt,  also  20  acres  each.  All 
these  claims  are  i)atented. 

Tiie  clay  is  a  white,  .semi-pla.stic  fiireclay.  It  does  not  dcvelo])  suffi- 
cient plasticity  to  be  used  alone,  and  is  of  value  principally  for  its 
refractoriness.  It  is  used  in  Los  Angeles  by  the  California  Clay 
Products  Comi)any,  as  an  ingredient  in  the  manufacture  of  saggers, 
and  also  in  San  Diego  by  the  Vitrified  Products  Corporation.  These 
companies  are  controlled  by  the  Victor  Kremer  Enterprises,  Victor 
Kremer,  president. 

Devkloi'MENT  AND  ]\IiNiNO :  A  number  of  test  pits  and  trenches  have 
been  dug,  ex])osing  clay  over  a  considerable  area.  ^Mining  is  being 
done  on  the  Pearl  claim,  where  a  loading  bin  has  been  built  and  a  small 
open  cut,  30  by  40  feet  in  area,  has  been  excavated.  The  ex])osed  baidc 
of  clay  is  10  to  12  feet  high.  One  carload  per  week  is  being  mined  and 
trucked  to  Cardiff. 

Sample  Xo.  36  was  taken  for  testing.     See  page  'Ml. 

Bibl:  State  Mineralogist's  Report  XXI,  p.  355. 

El  Cajon  Kaolin  Deposit.  The  deposit  is  located  on  Cajon  ^Mountain, 
at  an  elevation  of  2500  to  2700  feet,  41  miles  in  a  direction  X.  55  E. 
from  Lakeside.  It  is  now  ow^ned  by  the  American  Pottery  Company  ( ?) 
of  Los  Angeles.  The  holdings  comprise  two  claims  in  T.  14  S.,  R.  2  E., 
S.  B.  ]\I.,  on  or  near  Sec.  29,  approximately  one  mile  west  of  El  Cajon 
Peak,  but  practically  on  top  of  the  range. 

The  kaolin  was  formed  by  alteration  in  situ  of  an  ala.skite  or  similar 
])egmatitic  derivative,  containing  but  small  quantities  of  ferro-manga- 
nesian  minerals.  The  extent  of  alteration  varies  widely  within  com- 
paratively short  distances,  so  that  the  resultant  material  ranges  from 
slightly-plastic  kaolin  containing  an  excess  of  free  quartz  and  unde- 
composed  feldspar,  to  extremely  plastic,  fine-grained,  thoroughly- 
hydrated  kaolin.  Exposures  of  such  material  have  been  made  at 
various  points  on  the  mountain,  indicating  that  they  occur  in  a  zone 
that  has  a  general  northeast  strike. 

The  deposit  has  been  developed  by  a  number  of  t.iinnels,  shafts,  and 
open  cuts,  the  principal  tunnel  having  been  driven  m  a  northwesterly 

'  State  Mineralogist's  Report  XIV,  p.   685. 


202  DIVISION  OF  MINES  AND  MINING 

direction  for  a  distance  of  75  feet,  to  a  point  50  feet  below  the  surface. 
This  tunnel  is  connected  by  means  of  a  raise  to  a  small  open  pit,  or 
glory  hole.  The  material  exposed  by  these  workings  shows  all  of  the 
variations  indicated  above,  witli  six  feet  of  thoroughly  altered,  plastic 
kaolin  near  the  face.  During  1914  and  1916,  some  kaolin  from  these 
workings  was  sliipped  to  the  faience  tile  plant  of  the  former  California 
China  Clay  Products  Company  at  National  City.  The  total  quantity 
shipped  probably  did  not  exceed  400  tons,  to  judge  from  the  extent  of 
the  workings.  The  material  was  packed  b}^  mules  over  a  rough  and 
steep  trail  to  a  point  on  the  San  Diego  River,  then  hauled  by  wagon  to 
Lakeside,  at  a  cost  said  to  have  been  $7.50  per  ton,  exclusive  of  mining. 
Due  to  its  inaccessibility,  there  has  been  no  work  on  the  deposit  since 
1916,  excepting  annual  assessment  work. 

Two  samples,  Nos.  37  and  38,  were  taken  and  tested,  the  results  of 
which  are  given  on  page  259. 

Bibl:  State  Mineralogist's  Report  XXI,  p.  354. 

Gladding,  McBean  and  Company.  Office  of  Southern  Division  at  621 
S.  Hope  Street,  Los  Angeles.  This  company  owns  a  deposit  of  clay, 
of  Eocene  and  Pleistocene  age,  on  the  Las  Encinitas  Ranch  in  the  town- 
site  of  Olivenhain.  Tlie  property  includes  a  portion  of  Lot  18,  and 
adjoins  the  property  of  the  Vitrified  Products  Corporation  {q.  v.  post) 
on  the  west. 

At  the  time  of  visit,  on  June  9, 1925,  the  clay  was  being  mined  from  an 
o])en  cut,  tlie  floor  of  which  was  about  75  feet  square.  The  l)ank  was  30 
feet  high  at  the  face  of  the  pit.  ]\Iining  was  by  hand,  loading  into  small 
mine  cars,  whicli  were  trammed  over  a  trestle  to  a  bin,  from  which  auto 
trucks  were  loaded.  Three  or  four  cars  per  week  were  being  mined 
(luring  ])art  of  tlie  year,  the  annual  production  being  5000  to  7000  tons, 
which  was  used  in  the  company's  plants  in  Los  Angeles.  The  clay  is 
a  red-burning  material,  with  good  plasticity,  and  is  useful  in  face  brick 
and  sewer  pipe  mixes.  Sample  No.  35  was  taken.  The  test  results  are 
on  page  322. 

Since  the  property  was  visited,  it  is  understood  that  considerable 
drilling  and  other  development  work  has  been  done,  with  the  result 
that  excellent  deposits  of  fireclay  have  been  found,  in  addition  to  the 
red-burning  clay  already  known.  The  fireclays  are  said  to  closely 
resemble  the  Gros-Almerode  clays  of  Germany. 

H.  T.  Morris  of  Escondido  owns  a  deposit  of  clay  one  mile  south 
of  Richland  Station  on  the  Escondido  Branch  of  the  Santa  Fe  Rail- 
road. 

The  clay  occurs  in  a  low  hill  and  is  covered  by  black  adobe  .soil. 
The  deposit  has  not  been  developed  and  good  exposures  of  the  fresh 
clay  are  lacking.  The  deposit  is  apparently  at  least  15  feet  in  thick- 
ness, and  underlies  .several  acres  of  land.  The  attempt  was  made  some 
time  ago  to  make  common  red  brick  from  this  clay,  but  it  Avas  unsuc- 
cessful largely  because  of  im])roper  mixing,  tempering,  and  firing  of 
the  brick.  Some  specimens  of  earthernware  made  from  this  clay  can 
be  seen  in  the  Chamber  of  Commerce  exhibit  at  Escondido. 

Sample  No.  41  was  taken  for  testing.     See  page  348. 

Bibl:  State  Mineralogist's  Report  XXI,  p.  355. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  203 

National  Brick  Company.  William  ]\Iulford,  president ;  Edward 
Harrie,  Jr.,  secretary.  Offices  and  i)lant  are  located  at  Twenty-fourth 
JStreet  and  National  Boidevard.  National  City.  The  holdings  of  the 
company  comprise  13  acres,  under  lease  from  S.  Christian,  of  National 
City.  The  company  is  manufacturing  common  red  brick  from  adobe 
clay.  The  clay  is  hauled  by  scrapers  to  a  liopper,  from  which  it  passes 
to  a  set  of  rolls,  where  the  clods  are  broken  up.  It  is  then  conveyed 
over  a  belt  conveyor  to  a  pug-mill,  from  which  it  passes  to  a  brick  press. 

The  brick  are  dried  in  sheds.  The  dried  brick  are  fired  in  ojien  oil- 
fired  kilns.  The  plant  is  driven  by  a  50-h.p.  electric  motor,  and  has  a 
capacity  of  36,000  brick  per  day.     Fifteen  men  are  employed. 

Old  Mission  Tile  Compayv/.  W.  C.  Mitchell,  president;  J.  F.  Keenan, 
secretary;  P.  0.  McCarthy,  treasurer.  Office  and  plant  in  North  San 
Diego.  This  company  was  organized  in  1927  with  a  capitalization  of 
$50,000,  to  manufacture  hand-made  roofing  and  promenade  tile.^ 
Further  details  are  lacking. 

Pacific  Clay  Products  Company.  Wm.  Lacy,  president ;  Robert 
Linton,  vice  president  and  general  manager.  Offices,  1151  South 
BroadAvay  Street,  Los  Angeles.  Three  miles  east  by  road  from  Farr 
Siding,  which  is  on  the  Santa  Fe  Railroad  one  mile  south  of  Carlsbad, 
is  one  of  the  clay  properties  owned  and  operated  by  the  Pacific  Clay 
Products  Company  of  Los  Angeles.  The  property  was  formerly  a 
part  of  the  Kelley  Ranch,  and  comprises  25  acres. 

The  clay  beds  are  exposed  on  a  low  rounded  hill.  The  upper  10 
to  15  feet  consists  mainly  of  a  white  plastic  vitrifying  clay  which  is 
used  in  a  mix  for  the  manufacture  of  face  brick  and  other  products. 
This  clay  is  slightly  iron-stained,  and  is  mixed  with  a  small  quantity 
of  bluish  plastic  clay. 

Underlying  the  bed  of  white  clay  is  a  bed  of  mixed  yellow  and  blue 
clay  of  undetermined  thickness.  This  clay  is  also  plastic  and  will  doubt- 
less be  extensively  utilized  as  development  of  the  property  advances. 

Development  and  IMining  :  The  clay  has  been  prospected  by  means 
of  a  number  of  test  pits  on  the  property.  Mining  was  formerly  done 
with  horse  scrapers  and  plows  and  with  a  wheel  scraper  drawn  by  a 
tractor  but  more  recently  a  "Bear  Cat"  shovel  has  been  installed.  See 
photo  No.  61.  A  bench  has  been  established  for  mining  the  upper  bed 
of  white  clay  separately  from  the  yellow  clay.  The  exposed  bank  of 
white  clay  is  275  feet  long.  A  motor  truck  is  used  to  haul  the  clay 
to  Farr  Siding.    The  production  is  20,000  tons  per  year. 

Sample  No.  39  of  the  white  eluy,  and  sample  No.  40  of  the  yellow 
clay  were  taken  for  testing.     See  pages  296  and  322. 

Other  remnants  of  this  same  clay  bed  occur  in  various  places  on  the 
Kelley  ranch.  Some  test  pits  have  been  dug,  but  no  deposit  as  satis- 
factory in  quality  or  extent  as  that  owned  by  the  Pacific  Clay  Products 
Company  has  been  disclosed. 

Bibl:  State  Mineralogist's  Report  XXI,  p.  356. 

San  Diego  Tile  and  Brick  Company.  Wm.  Roffe,  president  and 
manager.  Office  in  San  Diego.  This  companj^  controls  100  acres  of 
land  in  Rose  Canyon.    The  clay  pit  and  brick  yard  are  on  the  west  side 

'Clay-Worker,  August,  1927,  p.  123. 


204  DIVISION  OF  MINES  AND  MINING 

of  the  canyon,  3.2  miles  by  road  north  from  Balboa  Avenue,  Coast 
highwav.  The  material  used  is  a  Tertiarv  shale,  which  is  for  the  most 
part  thin-bedded,  moderately  hard,  and  generalh'  yellowish  or  yellowish 
g;ray  in  color.  The  same  formation  persists  on  the  west  side  of  the 
canyon  for  several  miles. 

The  clay  is  scraped  into  chutes  alongside  of  the  Rose  Canyon  Road, 
at  a  point  50  feet  vertically  above  the  yard.  The  clay  bank  at  present 
exposed  is  about  75  feet  high  at  its  highest  point,  and  300  feet  long. 
Practically  no  overburden  is  present.  Common  red  brick  and  hollow 
building  tile  are  made  by  the  stiff  mud  process.  Drying  is  done  partly 
in  the  open  air  and  partly  under  shed.  The  dried  brick  are  fired  in 
open  oil-fired  kilns.  The  plant  is  oi)erated  as  required  to  supply  the 
local  demand. 

Sample  No.  30  was  taken  for  testing.     See  page  339. 


i^V 


^':-A--'  '    --  -■^.r         "--  '  --*  • 


'-^  -  ■  't^,'';::^  •^'^^W 


Photo  No.  61.      "Bear  Cat"  shovel  at  Kelly  No.  1  mine,  Pacific  Clay  Products  Co., 

p-arr    siding,    San    Diego    County.       (Samples    No.    39    and    40.)       (Photo    by 
courtesy  of  the  company.) 

Union  Brick  Company.  J.  W.  Rice,  secretary.  Offices,  3565  Third 
Street,  San  Diego.  The  plant  is  1.1  miles  north  of  Balboa  Avenue, 
Coast  Highway,  on  El  Camino  Real  through  Rose  Canyon.  It  is  about 
two  miles  south  of  the  yard  of  the  San  Diego  Brick  and  Tile  Company. 
The  shipping  point  is  Ladrillo  Station  on  the  Santa  Fe  Railroad. 

The  clay,  while  apparently  belonging  to  the  same  stratigraphic  series 
as  that  of  the  San  Diego  Tile  &  Brick  Company's  deposit,  is  somewhat 
different  in  character,  and  consists  mainly  of  a  loose  conglomerate 
composed  of  pebbles  and  boulders  of  all  sizes  up  to  two  feet  in  diameter, 
intermingled  with  loose  yellowish  clay.  Underlying  this  material  is  a 
bed  of  plastic  clay  shale,  blue-gray  in  color. 

The  clay  is  mined  with  Fordson  tractors  and  scrapers  Avhich  dump 
the  material  into  a  chute  leading  to  the  brick  yard  located  in  the 
bottom  of  the  canyon.  Common  red  brick  only  is  made  at  this  point 
which  is  equipped  with  dry  pan  and  two  electric-driven  presses.     Oil- 


CLAY  RESOURCES  AND  CERAi^flC  INDUSTRY 


20;') 


firod  oi)eii  Hold  kilns  aro  used.     It  is  said  tliat  the  clay  lias  vcrv  little 
shrinkaji-p  durinji:  tho  briek-inakino:  process. 

Sample  No.  -"{l   was  taken   I'oi-  testinj;.      See  \)i\\xo  'MO. 

Vitrified  Producis  ('orporafion.  Victoi-  Kroiuoi",  i)i-esident ;  George 
Kumiuer,  jreneral  manaj-er;  John  F.  Koonan,  supei'intendent.  Sales 
office,  522-24  Spreckels  lUiilding,  San  Diego;  general  offices  and  plant 
in  North  San  Diego.  This  jilant  started  operations  in  November,  1928, 
to  make  semivitiv^ons  hollow  tile,  building  tile,  and  brick.  The  com- 
pany owns  two  clay  deposits,  one  at  Linda  Yista,  the  other  near  Carditf. 

Cardiff  Deposit:  This  is  a  dei)osit  of  fireclay  on  the  Las  Encinitas 
Ranch  in  the  townsite  of  Olivenhain.  The  holdings  consist  of  a  portion 
of  lot  18  in  Rancho  Las  Encinitas,  and  comprises  16.6  acres.  The 
property  formerly  belonged  to  the  Wiro  famil}',  and  is  known  to  local 


r'-'m^ 


4^ 


Urn,      .-r; 


,^;--?^7*.^>ri^», 


I'HuTo  No.  62.     W'iro  Mine.     Fireclay  deposit  east  of  Cardiff.  San  Diego  County, 
owned  by  the  Vitrified  Products  Co.  of  San  Diego.      (Sample  No.  34.) 

inhabitants  as  the  Wiro  Mines.  It  is  5.7  miles  by  road  from  Cardiff  in 
an  ea.sterly  direction. 

The  fireclay  has  been  exposed  by  two  small  open  cuts,  each  of  which 
is  abont  50  feet  square,  Avith  a  bank  of  15  to  20  feet  in  height.  The 
bed  of  fireclay  is  from  10  to  12  feet  thick,  and  is  overlain  by  a  thin 
layer  of  soil  and  yellow,  sandy  clay.  The  beds  are  nearly  horizontal. 
Sample  No.  33  was  taken  from  the  north  pit,  and  sample  No.  34  is  from 
the  south  pit,  and  the  test  results  are  on  page  2S7.     See  photo  No.  62. 

Underlying  the  fireclay  is  a  bed  of  soft,  loosely  consolidated  sand- 
stone containing  clay  as  filling  material.  The  fire  clay  is  moderately 
hard  and  varies  in  color  from  a  buff  to  blue-gray  and  light  purple. 

At  the  time  of  visit  (June,  1925),  one  to  two  cars  per  week  were  being 
rained  and  shipped  from  a  siding  one  mile  south  of  Cardiff. 

Linda  Vista  Deposit  :  This  deposit  is  located  on  the  south  side  of  the 
Santa  Ee  Railroad  at  Mile  25],  about  two  miles  north  of  Linda  Vista 
Station,  in  Sec.  9,  T.  15  S.,  R.  3  W.,  S.  B.  M. 


206  DIVISION  OP  MINES  AND  MINING 

The  holdintrs  include  the  Ni  and  the  NEJ  of  the  SW]  of  the  section, 
a  total  oi'  'MW  aci'es.  most  of  wliieii  is  appai-ently  underlain  by  the 
clay  beds. 

At  the  time  of  visit  on  June  !),  l!)2r),  Ihe  deposit  had  been  opened  by 
an  electric  shovel  along-  a  face  300  feet  long  and  50  feet  high,  adjacent 
to  and  adjoining  the  railroad  tracks.  The  material  is  a  clay  shale, 
light  yellow  in  color,  and  the  individual  strata  are  from  a  fraction  of 
an  inch  to  one  or  two  feet  in  thickness.  Two  or  three  beds  of  siliceous 
sandstone  about  one  foot  thick  are  interbedded  with  the  clay  shale. 
These  are  sorted  from  the  clay  whenever  possible.  In  places  the  clay  is 
more  santly  than  in  others,  but  is  seldom  too  sandy  foi'  satisfactoiy  use. 
The  overburden  is  thin,  varying  from  6  inches  to  3  feet  in  thickness. 
The  same  formation  is  quite  extensive  in  this  locality  and  can  be  traced 
for  at  least  a  mile  along  the  Santa  Fe  tracks  toward  Linda  Vista.  The 
total  thickness  of  the  clay  beds  is  probably  not  less  than  100  feet. 

At  the  time  of  visit  about  200  tons  per  week  were  being  shipped  to 
the  San  Diego  plant.  When  the  plant  is  operating  at  full  capacity, 
300  tons  per  w^eek  are  shi]>ped. 

8am])le  No.  32  was  taken  for  testing.     See  page  322. 

San  Diego  Plant:  At  the  plant  in  North  San  Diego  hollow  tile  and 
building  tile  are  made  by  mixing  25%  of  the  Cardiff  tireclay  with  75% 
of  the  Linda  Vista  clay.  The  material  is  crushed  to  ^  inch  and  is  fed 
from  the  crusher  bin  into  a  trough  mixer,  where  it  is  tempered  with 
water.  The  tempered  clay  passes  through  an  auger  machine  and  the 
tile  are  cut  with  an  automatic  wire  cutter.  The  green  tile  are  then 
hand-loaded  on  triple-deck  trucks  and  trammed  to  the  drying  shed. 

When  not  working  at  full  capacity,  the  drying  is  completed  in  three 
or  four  da3^s,  but  when  crowded  to  capacit}-  only  one  day  is  allowed  for 
this  part  of  the  process.  The  drying  is  finished  in  oil-fired  drying 
ovens  where  the  heat  is  controlled  according  to  the  amount  of  moisture 
remaining  in  the  tile.  At  times  the  dryer  temperature  is  so  high  as  to 
scorch  the  wooden  pla.tforms  of  the  trucks. 

The  common  brick  are  fired  in  open  field  kilns,  using  oil  as  fuel. 
The  other  shapes  are  fired  in  oil-burning  round  down-draft  kilns.  The 
firing  temperature  is  from  2000°  to  2100°  F.  for  4|  to  5  days.  An 
equal  period  is  allowed  for  cooling.  The  firing  range  of  the  clays  in 
use  is  200°  F.  The  brick  and  tile  are  remarkably  uniform  in  color, 
which  is  a  pink  bordering  on  red.  There  is  very  little  difficulty  with 
lost  ware  and  all  of  the  products  are  strong  and  free  from  cracks.  The 
drying  shrinkage  amounts  to  1  in  11-J,  and  there  is  no  cracking  during 
the  drying  of  the  tile  which  are  placed  on  the  side  rather  than  on  end. 
The  firing  shrinkage  is  exceptionally  low. 

The  capacity  of  the  plant  is  50,000  brick  and  50,000  hollow  tile  per 
day. 

Bibl:  State  Mineralogist's  Reports  XIV,  pp.  685-688;  XX,  p.  369; 
XXI,  pp.  354-358.    Bull.  38,  pp.  227,  254. 

SAN    FRANCISCO   COUNTY. 

The  area  of  San  Francisco  County  is  43  square  miles,  and  tlie  popu- 
lation is  506,676  (1920  census).  The  only  mineral  production  in  the 
county  is  crushed  rock,  sand  and  gravel.     A  number  of  brick  yards  at 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  207 

oiu'  lime  ()|)t'i-a1('(l   in   the  county,  hut    hiiul   is  uow  more  valuable  for 
otluT  i)uri)oses. 

The  only  ceramic  plants  in  the  county  ai-e  an  art  ^vare  pottery  at 
2928  Baker  Street,  San  Fraiu'iseo,  owned  and  oi)erated  hy  JaJanivich 
and  Olsen,  and  a  dental  ])oreelain  lahoratoi-y  at  8:)()  Market  Street, 
known  as  Tara's  Porcelain  Lahoi'ofory.  Jalanivich  and  Olsen  are 
makinp:  an  attractive  line  of  glazed  pottery,  usinf;  a  buff -burning  body 
and  lead  glazes.  Their  output  is  all  liand-niolded  on  a  potter's  wheel. 
It  is  tired  in  a  round  kiln,  approximately  3-ft.  inside  diameter,  of  tlieir 
own  design  and  built  by  the  gas  company,  city  gas  being  used  for  fuel. 
The  clav,  from  California  sources,  is  fired  up  to  2000°  and  the  glaze 
to  KiOO'^-lTOO". 

SAN   JOAQUIN   COUNTY. 
General    Features.' 

The  county  lies  mainly  in  the  great  valley  of  the  same  name  in  the 
central  portion  of  the  state.  It  is  bounded  on  the  north  by  Sacramento 
County,  on  the  east  by  Amador,  Calaveras,  and  Stanislaus.  The  latter 
county  extends  around  and  adjoins  it  on  the  south  also.  Contra  Costa 
and  Alameda  counties  lie  west  of  it. 

Stockton,  the  county  seat  and  largest  city,  has  water  transportation 
facilities,  as  well  as  rail.  The  area  of  the  county  is  1448  square  miles, 
aiul  its  population  is  79,905  (1920  census).  By  far  the  greatest  part 
of  its  area  is  made  up  oF  farm  lands  ;  the  so-called  'delta'  region  adjacent 
to  Stockton  being  noted  for  its  rich  peat  soil  and  heavy  crops. 

The  luost  extensive  geological  formation  exposed  consists  of  uncon- 
solidated sands,  gravels  and  clays  of  Quaternar\'  age,  which  compose 
the  nearly-level  valley  floor.  Tlie  western  edge  of  this  formation  fol- 
lows closely  the  Southern  Pacific  railroad  line  down  the  west  side  of 
the  valley  from  Bethany  to  Vernalis.  The  corner  of  the  county,  south- 
west of  the  railroad,  is  composed  of  marine  sandstone,  and  diatomaceous 
and  clay  shales  of  Tertiary  and  Cretaceous  ages  in  the  northern  part. 
Its  south  half  is  rugged  and  broken,  as  the  Franciscan  rocks,  typical  of 
the  Coast  Range,  including  slates,  cherts,  linu'stones  and  sandstones, 
witli  much  scliist  and  ser})entine,  are  exclusively  in  evidence. 

Unconsolidated  sands,  gravels  and  clays  extend  practically  to  the 
county  line  on  the  eastern  side  of  the  valley,  the  only  other  rocks 
exposed  being  two  small  areas  of  extrusive  volcanic  rocks,  just  east 
and  north  of  Bellota. 

Comparatively  few  minei-al  substances  are  found  in  San  Joaquin 
County,  and  of  these  the  most  im])ortant  are  nonmetallic  structural 
and  industrial  materials  and  natural  gas.  Gold,  silver  and  platinum 
have  been  obtained  by  dredging  in  ]Mokelumne  River.  Clay  and  clay 
products  accounted  for  more  than  half  the  total  mineral  production  of 
the  county  in  1923. 

Clay   Resources. 

Common  clays  suitable  for  the  manufacture  of  brick  are  abundant 
in  the  county,  and  two  brick  yards  are  in  operation.  High-grade  clays 
were  at  one  time  produced  near  the  San  Joaquin  and  Alameda  county 
line,  in  the  vicinity  of  Tesla  and  Carnegie,  and  were  utilized  at  the 

*  Laizure,  C.  McK.,  State  Mineralogist's  Rept.  XXI,  p.   1S4. 


208  DIVISION'  OF   MIXES  AXn  MINIXO 

l)]aiit  of  the  Carnegie  Brick  and  Pottery  Company,  which  has  been 
(lisnianthMl  for  many  years.  See  under  Alameda  County  for  further 
(h'tails. 

One  of  the  important  fire  brick  plants  of  tlie  state,  that  of  the  Stock- 
ton Fire  Brick  Company,  is  operating  in  Stockton.  The  i)lant  is 
strategically  situated  with  res])ect  to  the  clay  mines  of  Amador  and 
Placer  counties,  and  is  within  the  range  of  chea})  transportation  to  tlie 
marketing  centers. 

San  Joaquin  Brick  Co.  I.  P.  Stine,  secretary-manager;  Ernest 
Rossi,  jjlant  superintendent.  Home  office,  33  South  El  Dorado  Street, 
Stockton.  The  property  is  located  on  a  60-acre  tract  on  Roberts 
Island,  six  miles  by  road  southwest  from  Stockton.  Common  red  brick 
is  the  sole  product.  The  clav  is  an  extremely  sandy  bottom-land  loam. 
The  water  level  lies  within  six  feet  of  the  surface,  so  that  economical 
mining  has  always  been  a  serious  problem.  A  horse-scraper  is  used 
above  the  water  level,  dumping  through  trap  doors  into  horse-drawn 
cars  operating  on  a  light  industrial  track.  A  gasoline  locomotive  was 
])urchased  and  tried  in  place  of  horses  for  haulage,  but  the  track  was 
not  of  sufficient  weight  to  obtain  satisfactory  results. 

Below  the  water  level,  the  clay  is  excavated  with  a  ^Marion  steam 
shovel  mounted  on  a  barge.  The  clay  is  dumped  along  the  bank,  and 
allowed  to  dry  in  the  air  before  it  is  reclaimed  by  the  horse  scraper. 

The  soft-mud  process  is  used  for  shaping  the  brick.  The  clay  is 
given  a  double  pugging  before  passing  to  a  6-mold  press.  A  continu- 
ous rope  conveyor  takes  the  brick  from  the  press  to  the  drying  sheds. 
The  sandiness  of  the  clay  is  indicated  by  the  fact  that  the  drying  ])eriod 
in  warm  weather  is  only  three  days,  with  a  maximum  of  five  days  in 
cooler  Aveather. 

A  Hoffman  continuous  kiln  burning  coal  screenings  is  used  for  firing. 
The  kiln  is  175  feet  long,  with  12-ft.  by  12-ft.  chambers.  The  firing 
cycle  is  14  days,  and  the  capacity  is  24,000  brick  per  day.  The 
machinery  is  o])erated  by  electric  power.  The  total  installed  ca]iacity 
of  the  motors  is  100  horsepower.     Forty  men  are  employed. 

Bibl:  State  Mineralogist's  Report  XXI,  p.  188. 

Stockton  Brirk  and  Tile  Co.  Ralph  Wilcox,  president ;  Paul  Weston, 
secretary;  G.  Birtolini,  plant  superintendent.  Home  office,  245  North 
El  Dorado  Street,  Stockton.  The  plant  is  on  McKinley  Avenue  near 
the  southern  boundary  of  the  city  of  Stockton,  about  one-half  mile  west 
of  the  Municipal  Baths.  A  Southern  Pacific  spur  track  runs  to  the 
l)lant.  The  plant  was  built  in  1921.  Common  brick  and  some  hollow 
building  tile  are  manufactured,  using  surface  clay  from  the  property. 

The  claj^  is  a  bottom-land  deposit  of  yellowish  sandy  loam  and  is 
mined  to  a  depth  of  15  feet  below  the  surface  by  horse-drawn  scrapers. 
The  clay  is  found  at  greater  depths,  but  is  below  the  water  level.  The 
scrapers  deliver  the  clay  to  a  dry  pan,  from  which  the  crushed  product 
is  elevated  by  a  bucket  elevator  to  a  pug-mill  and  auger  machine.  The 
brick  are  taken  from  the  wire-cutter  belt  by  hand  and  loaded  on  trucks 
wliich  are  trammed  by  hand  to  oil-fired  tunnel  driers. 

Firing  is  done  in  a  Hoffman  continuous  kiln.  The  capacity  of  the 
kiln  is  450,000  brick,  and  25,000  brick  are  set  and  drawn  each  day. 
Coal  screenings  from  Utah  coal  are  used  as  fuel.     The  coal  lioles  are 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  209 

Spaced  three  feet  apart.  One  man  on  each  8-hr.  sliift  attends  to  the 
firing.  The  fires  must  be  carefully  controlled,  as  the  kiln  is  too  short 
for  successful  iirin<;'  if  irregular  Hud  nations  in  temperature  are  i)er- 
mitted.     Natural  stack  draft  is  used. 

In  order  to  keep  the  plant  in  continuous  operation  during  the  year, 
it  is  customary  to  shape  40,000  brick,  or  the  ecpiivalent  volume  of  brick 
and  hollow  tile,  per  day,  during  the  summer  and  fall.  Half  of  this 
output  of  green  ware  is  stored  for  firing  during  the  winter  months,  so 
that  it  is  not  necessary  to  operate  the  pit  or  the  auger  machine  during 
the  wet  season. 

The  plant  emploj^s  25  men  during  the  summer  and  about  15  men 
during  the  winter.  The  annual  output  is  over  3,000,000  brick,  or  an 
equivalent  volume  of  brick  and  hollow  tile.  The  hollow  tile  production 
is  never  a  large  proportion  of  the  total.  All  machinery  is  operated  by 
electric  power. 

Bibl:  State  Mineralogist's  Report  XXI,  p.  188. 

Stockton  Fire  Brick  Co.  John  T.  Roberts,  i)resident ;  Percy  T.  Cleg- 
horn,  secretary ;  E.  H.  Horner,  plant  superintendent.  JMain  office,  12 
Russ  Building,  San  Francisco.    Plant  address,  P.  0.  Box  314,  Stockton. 

The  company's  plant  is  just  west  of  the  Southern  Pacific  railroad  at 
the  foot  of  S.  California  Street,  Stockton.  See  photos  No.  6:}  and  64. 
The  outi)ut  includes  several  different  grades  of  fireclay  brick  and 
special  shapes,  high-temperature  fireclay  cement,  and  diatomaceous 
insulating  brick.  The  companj^  owns  or  leases  deposits  of  most  of 
the  raw  materials  in  use  at  the  plant,  the  most  important  of  these  being 
Edwin  clay  (No.  120,  p.  272),  from  Jones  Butte  near  lone;  lone  sand 
(No.  140,  p.  280),  from  the  pit  of  the  lone  Fire  Brick  Co.,  and  Lincoln 
fireclay  (sample  No.  280,  p.  305),  from  the  newly  developed  pit  of  a 
subsidiai-y  company,  the  Clay  Corporation  of  California.  Quartz  for 
grogging  some  of  the  grades  of  fire  brick  is  purchased  from  various 
California  sources,  mainly  in  Placer  County,  and  diatomaceous  shale 
for  the  manufacture  of  insulating  brick  and  special  shapes  is  purchased 
from  producers  in  Santa  Barbara  County. 

The  princii)al  grades  of  fire  brick  are  as  follows:  'Gasco  XX,"  quartz 
grogged,  auger-made,  single  pressed ;  '  Stockton, '  quartz  grogged,  auger- 
made,  repressed ;  '  Gasco  R, '  quartz  grogged,  auger-made,  repressed ;  and 
'Carnegie,'  which  is  grogged  with  calcined  fireclay,  hand-made  in 
sanded  molds,  and  repressed.  The  'Carnegie'  brick  is  the  best  grade 
of  standard  brick  being  produced  at  present  for  resisting  high  tem- 
peratures under  adverse  load  and  spalling  influences.  Among  the 
specialties  regularly  produced  are  a  high-grade  checker-brick  which  is 
made  from  a  mixture  grogged  with  calcined  clay  and  shaped  on  an 
end-cut  auger  machine,  and  runner-brick,  made  from  a  similar  mixture, 
formed  on  an  auger-machine,  and  then  passed  to  a  specially  designed 
machine  for  making  the  joints  and  cutting  the  side-holes. 

The  mixtures  are  prepared  by  dry-pan  grinding,  followed  by  pug- 
mill  tempering  for  the  material  that  is  to  be  hand-molded. 

All  of  the  shapes  except  runner  brick  are  dried  in  waste-heat  tunnel 
driers.  The  runner  brick,  which  require  especially  uniform  drying 
on  all  sides  during  the  shrinkage  i)eriod,  are  dried  in  a  Carrier  ejector 
humidity  drier,  which  is  operated  on  a  13  to  15  hr.  schedule,  beginning 

14—54979 


210 


DIVISION  OF  MINES  AND  MINING 


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CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


211 


with  a  tliree-hour  [xM-iod  at  Ho""  F.  and  40'/  humidity,  and  finished 
at  240°  to  250  F.  with  steadily  declinin<>-  humidity.  The  brick  are 
set  on  tlie  drier  ears  in  a  direction  parallel  to  the  dii-eetion  of  the  air 
current  in  the  drier,  so  that  the  air  passes  tlirou^ih  and  around  the 
brick  simultaneously,  thus  drying  the  inside  and  outside  of  the  brick 
at  the  same  rate. 

The  manufacture  of  diatoniaeeous  insulating'  brick,  known  by  the 
ti-ade  name  'Diatex,'  is  becoming  an  increasingly  iini)ortant  part  of  the 
0|)erations  of  the  phmt.  Standard  9-in.  brick  and  many  special  shapes 
are  made.  They  are  liaud  molded  from  diatomaceous  shale  containing 
sufficient  clay  for  boiidiiiu.     Slow  and  cai-eful  uniform  drying  is  neces- 


Photo  No.   64.     Clay  bins  and  dry  pans  In  plant  of  the  Stockton  Fire  Brick 
Company.      (Photo   by   courtesy   of   the  company.) 

sary  to  avoid  loss  by  warping  or  cracking.  In  connection  with  the 
development  of  this  i)roduct  a  conductometer,  the  i^rinciple  of  which 
has  been  described  by  K.  I).  Pike,^  was  constructed  in  the  laboratory, 
for  the  purpose  of  comparing  the  heat  conductivities  of  the  various 
experimental  mixtures. 

The  fireclay  ])roducts  are  fired  in  12  oil-fired  round  down-draft 
kilns,  which  are  of  various  sizes  from  12-ft.  to  :32-ft.  in  diameter,  with 
capacities  ranging  from  80  to  400  tons  each.  The  usual  firing  cycle 
is  seven  to  eight  days  firing,  to  a  temperature  of  1370°  C,  correspond- 
ing to  cone  11  down,  followed  by  a  cooling  period  of  equal  length. 

•  Pike,  R.  D.,  Need  for  more  refractory  heat  insulators :  Pro])osed  conduetometers 
for  measuring  thermal  conductivity:  Jour.  Amer.  Cer.  Soc,  5,  554,  August,  1922. 


212  DIVISION  OF  MINES  AND  MINING 

The  insulating  brick  are  fired  in  fonr  12-ft.  hy  23--ft  rectangular 
kilns. 

liJase-metal  thcrinofouijles  with  automatic  recorders  are  installed  in 
all  kilns  for  the  accurate  control  of  the  firing  cycle. 

The  plant  is  noteworthy  for  the  high  degree  of  technical  control  to 
which  all  operations  are  subjected,  and  for  the  continual  improvements 
that  are  being  made  in  the  processes  of  manufacture  and  in  the  (juality 
of  the  finished  product,  through  the  cooperation  of  an  efficient  technical 
staff  and  a  progressive  management. 

An  average  of  110  men  are  employed. 

Bibl  (Clay  resources  of  San  Joacjuin  Count v)  :  State  Min.  Bur. 
Bull.  38,  pp.  227-228;  Prel.  Kept.  7,  pp.  91^95;  Kept.  XIV,  pp. 
607-610,  and  XXI,  pp.  188-190. 

SAN    LUIS  OBISPO  COUNTY. 
General    Features.^ 

San  Luis  Obispo  County  borders  on  the  Pacific  Ocean  and  occupies 
a  position  midway  between  San  Francisco  and  Los  Angeles.  It  is 
bounded  on  the  north  by  Monterey  County,  on  the  east  by  Kern  and 
on  the  south  by  Santa  Barbara.  It  contains  3334  square  miles  and 
has  a  population  of  21,893  (1920  census).  The  coast  line  of  the  South- 
ern Pacific  railroad  passes  through  the  county  from  north  to  south. 
The  railroad  follows  Salinas  River  Valley  through  Paso  Robles  to  a 
point  near  Santa  Margarita,  thence  it  crosses  the  Santa  Lucia  Range 
via  Cuesta  Pass,  reaching  San  Luis  Obispo  at  the  foot  of  the  grade, 
and  the  ocean  near  Pismo.  It  continues  south  along  the  ocean  shore, 
giving  through  transportation.  The  Pacific  Coast  railroad  (narrow 
gauge)  connects  Port  San  Luis  with  San  Luis  Obispo  and  continues  to 
Santa  Maria  and  other  points  in  Santa  Barbara  County.  The  paved 
coast  highway  closeh-  parallels  the  Southern  Pacific  railroad  through 
the  county. 

From  Santa  Margarita  fair  dirt  roads  extend  to  the  eastern  part  of 
the  county,  but  McKittrick,  in  Kern  County,  is  a  nearer  railroad  point 
to  this  section.  Steamer  service  is  available  at  Port  San  Luis.  This 
harbor  is  the  terminus  of  pipe  lines  from  the  San  Joaquin  Valley  oil 
fields  and  is  an  important  loading  point  for  oil  tankers. 

The  Coast  Range  mountain  system  traverses  the  county  from  north- 
west to  southeast.  Within  the  county  this  mountain  block  consists  of 
three  main  ranges,  the  Santa  Lucia  Mountains,  the  San  Luis  Range, 
and  the  San  Jose  Range. 

The  geology  of  that  portion  of  the  county  from  the  southern  boundary 
to  latitude  35°  30'  N.  and  from  the  coast  "to  longitude  120°  30'  W.  has 
been  described  and  mapped  in  detail  by  H.  W.  Fairbanks.-  A  discus- 
sion of  the  geology  of  the  countv  with  relation  to  petroleum  resources 
will  be  found  in  Bulletins  Xo.' 69  and  Xo.  89  of  the  State  Mining 
Bureau.     A  folio  of  geologic  maps  accompanies  Bulletin  Xo.  69. 

As  indicated  on  the  Bureau's  geological  map  of  the  state,  the  Santa 
Lucia  Range  from  San  Luis  Obispo  northwestward  to  the  northern 
boundary  line  is  made  up  of  Franciscan  rocks,  including  slates,  cherts, 

'  From  Laizure,  C.  McK.,  San  Luis  Obispo  County :  State  Mineralog-ist's  Rept. 
XXI.   pp.    499-501,    1925. 

=  Fairbanks,  H.  "W^,  San  Luis  Folio,  No.   101 :  U.  S.  Geological  Survey. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  211] 

limestones,  aii,d  sandstones,  witli  nuicli  serpentine  and  many  dikes  and 
intrusions  of  deeji-seatod  iji'iieous  roeks.  On  the  tlanks  of  tlie  range  are 
narrow  belts  of  Cretaeeous  sandstone  and  shales.  Southeast  of  San 
Luis  Obispo  the  formations  are  mainly  Tertiary  marine  sandstones 
and  diatomaeeous  shales.  Unconsolidated  sands,  jijravels,  and  clays 
extend  from  Pismo  to  Santa  IMaria  River  and  well  up  tlie  valley  of  the 
Santa  Maria.  East  of  Santa  Margarita  there  is  a  large  area  in  which 
granite  predominates.  The  balance  of  the  county  lying  east  and  north 
of  the  Santa  Lucia  Range  consists  almost  entirely  of  sedimentary  rocks 
of  Tertiary  age,  shales,  sandstones,  tuffs,  and  gravels  with  an  area  of 
Quaternary  sediments  comprising  Cai-rizo  Plain. 

Among  the  mineral  resources  of  the  county,  both  developed  and 
undeveloped,  are  asphalt,  bituminous  rock,  brick,  chroniite,  coal,  copper, 
diatomite,  gypsum,  iron,  limestone,  marble,  mineral  water,  onyx, 
l)etroleum,  quicksilver,  soda,  aiul  miscellaneous.  Miscellaneous  stone, 
l)etroleum,  brick,  and  mineral  water  are  the  principal  commercial 
mineral  products  at  present. 

Clay   Resources. 

There  are  no  known  deposits  of  high-grade  clays  in  this  county,  but 
red-burning  clays  suitable  for  making  brick  occur  in  the  vallej^  silts  of 
recent  origin  at  various  places.  Since  the  population  of  the  county  is 
small,  the  demand  for  claj'  i^roducts  is  limited,  and  a  single  common- 
brick  plant  at  San  Luis  Obispo  sup])lies  the  market  of  the  county  as 
well  as  of  a  few  nearby  towns  in  Santa  Barbara  and  Monterey  counties. 
The  territory  to  the  south  is  supplied  by  brick  yards  in  Santa  Barbara, 
while  plants  in  San  Jose  furnish  brick  for  the  communities  in  Monterey 
and  San  Benito  counties. 

San  Luis  Brick  Works.  Owned  and  operated  by  Faulstick  Bros., 
San  Luis  Obispo.  This  plant,  formerly  known  as  the  San  Luis  Brick 
C^ompau}',  is  located  one  mile  south  of  town,  near  the  lines  of  the 
Soutliern  Pacific  and  Pacific  Coast  railroads.  The  clay  is  a  yellowish 
loam,  with  little  or  no  overburden.  The  proportion  of  sand  is  sufficient 
to  prevent  excessive  shrinkage  and  cracking  in  the  brick-making  pro- 
cess, yet  is  not  so  high  as  to  interfere  with  the  binding  proj)erties  of 
the  clay.  The  clay  is  mined  to  a  depth  of  15  feet  by  hand  shoveling 
into  dump  cars,  which  are  hauled  up  an  incline  by  a  steam  winch,  to 
dump  through  a  hop])er  into  a  10-foot  dry  pan.  After  screening,  the 
fines  pass  to  a  ])ug-mill,  then  to  an  American  Clay  Machinery  Co. 
auger  machine  e()uipi)ed  with  a  Preese  cutter.  The  oversize  from  the 
screen  is  returned  to  the  dry  pan. 

The  brick  are  dried  in  the  open  without  auxiliary  heat.  This 
requires  an  average  of  three  weeks.  P.iirning  is  done  in  open  field 
kilns,  usually  Avith  18  arches,  each  kiln  containing  590,000  brick.  Heat 
is  supplied  by  oil,  with  steam  atomization.  Firing  requires  five  days, 
and  cooling  about  three  weeks. 

The  plant  operated  three  months  during  the  season  of  1925,  producing 
about  1,500,000  brick.  Twenty-eight  men  are  employed  when  in  full 
operation.      See  ))hoto  No.  65. 

Bibl:  State  Mineralogist's  Report  XXI,  ]).  505. 

Santa  Margarita.  Two  miles  south  of  Santa  IMargarita  is  an  extensive 
undeveloped   deposit   of   red-burning   shale.        The   deposit    is    easily 


214 


DIVISION  OF  MINES  AND  MINING 


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CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  215 

accessible  at  a  point  2.0  miles  (by  road)  south  of  the  center  of  8anta 
]Marj;arita,  where  it  lies  in  a  broad  belt  between  the  state  hij^hway  and 
the  Southern  Pacific  railroad  for  a  distance  of  at  least  one-half  mile. 
The  strike  of  the  beds  is  S.  25°  E.,  and  the  dip  is  75°  NE. 

Two  samples  were  taken.  No.  216  was  taken  from  a  road  cut,  2.0 
miles  from  Santa  ]Mai'<>ai-ita.  Sample  No.  217  was  taken  from  the  same 
formation,  2.5  miles  from  Santa  Mar<iarita,  and  0.;]  miles  north  of  the 
northern  boundary  of  the  Santa  Barbara  National  Forest.  The  test 
results  are  on  page  827.  Tlie  material  would  be  well  suited  for  the 
manufacture  of  vitrified  red-burned  structural  ware. 

Bibl  (Clay  resources  of  San  Luis  Obispo  County)  :  State  Min. 
Bur.  Bull.  38,  p.  255;  Prel.  Kept.  7,  p.  95;  State  Mineralogist's 
Rept.  XV,  p.  679 ;  XXT,  p.  505. 

SAN    MATEO  COUNTY. 
General   Features. 

San  ]\Iateo  County  lies  on  the  San  Francisco  Peninsula,  south  of 
San  Francisco  city  and  county.  Its  southern  boundary  adjoins  Santa 
Clara  and  Santa  Cruz  mountains.  Its  area  is  447  square  miles,  and 
the  population  is  36,781   (1920  census). 

Aside  from  a  narrow  strip  of  alluvial  ])lain  along  the  shores  of  San 
Francisco  Bay,  the  entire  county  is  mountainous,  as  the  western  spur 
of  the  Coast  Range  extends  through  the  county.  The  jn-incijial 
geological  formations  exposed  in  the  mountainous  portion  of  the  county 
are  Franciscan  (Jura.ssic)  sandstones,  jaspers,  ser])entines,  etc. ;  Chico 
(Upper  Cretaceous),  Pliocene  and  Miocene  sedimentary  deposits, 
mainly  sandstones  and  shales,  and  granite. 

The  most  important  mineral  jiroducts  are  cement,  miscellaneous 
stone,  and  salt.  Jasper,  magnesium  chloride,  natural  gas,  petroleum, 
and  jiotash  are  also  ])roduced.  Small  amounts  of  barytes,  chromite, 
diatomite,  and  quicksilver  have  also  been  found. 

Clay   Resources. 

No  high-grade  clays  have  been  reported  in  the  county.  Deposits  of 
clay  and  shale  suitable  for  brick  making  are  ])lentiful. 

The  only  clay-working  plant  in  the  county  is  that  of  the  West  Coast 
Porcelain  Manufacturers,  described  below.  The  Steiger  Terra  Cotta 
and  Pottery  Works,  and  the  Baden  Brick  Company,  mentioned  in 
earlier  reports,  were  dismantled  many  years  ago. 

West  Coast  Porcelain  Manufacturers.  Henry  Weiss,  president  and 
general  manager ;  Ed.  Durant,  jilant  manager ;  T.  B.  Gotham,  superin- 
tendent and  ceramist.  The  i)lant  is  near  ^lillbrae  station  on  the  South- 
ern Pacific  Railroad.  Vitreous  sanitary  porcelain  is  the  only  product. 
The  body,  which  contains  50%  clay  and  50%  flint  and  feldspar,  is 
made  from  English  china  and  ball  claj^,  Tennessee  ball  clay,  Ottaw^a 
or  Illinois  sand  and  feldspar  from  Campo,  San  Diego  County.  Alber- 
hill  bone  clay  is  used  in  the  sagger  mix,  as  the  aluminous  structural 
clay;  lone  clays  as  the  binders. 

All  of  the  ware  is  shajjcd  by  casting,  and  the  sli])  room  is  one  of  the 
most  modern  and  best  equipi)ed  in  the  West.  Special  precautions  are 
taken  to  secure  uniformity  of  grinding  and  proportioning  and  freedom 
from  contamination. 


216  DIVISION  OP  MINES  AND  MINING 

The  body  is  prepared  by  tlie  dry-mix  process.  Tlu-ee  .SO-li]).  Crossley 
dry  pebble  mills  are  used  for  grinding  the  Ottawa  sand  and  feldspar. 
Seven  hours  grinding  is  necessary  for  each  batch  of  sand  or  feldspar. 
The  English  ball  clay  is  passed  through  a  disintegrator  to  crush  it  to 
less  than  §  in.  diameter.  The  Tennessee  ball  clay  does  not  require 
])revious  crushing.  The  dry  pulverized  materials  are  stored  in  bins 
from  which  they  are  weighed  out  for  the  casting  slip  batches.  Three 
double  casting  slip  blungers  are  used  for  the  preparation  of  the  slip, 
which  weigrhs  80  oz.  per  pint.  The  discharge  from  the  blungers  is 
passed  over  a  Ding  magnetic  separator  to  remove  any  particles  of 
metallic  iron,  then  through  a  100-mesh  screen,  and  finally  to  Crossley 
slip  agitators  below  the  floor  of  the  slip  room.  From  the  agitators  the 
slip  is  pumped  to  the  casting  room. 

A  small  blunger  and  a  70-leaf  round-rail  filter  press  are  used  to 
retreat  the  scrap  body-mix  from  the  casting  and  drying  departments. 
This  is  necessary  in  order  to  remove  the  alkali  which  is  added  to  all 
slips  as  a  deflocculator,  and  which,  if  left  in  the  rejected  material, 
Avould  build  up  in  the  casting  slip  to  the  point  Avhere  blisters  would 
form  on  the  ware  during  firing. 

The  glaze  batches  are  ground  in  a  Crossley,  style  B  pebble  mill,  8  feet 
diameter  and  5  feet  8  inches  long,  driven  by  a  20-hp.  induction  motor. 
When  grouiul,  the  slip  is  passed  through  a  100-mesh  screen,  and  is 
pumped  into  a  Patterson  single-action  glaze  agitator,  where  it  is  kept 
in  suspension  until  drawn  off  for  use.  A  magnetic  separator  is  used 
to  remove  any  particles  of  iron  that  might  accidentally  have  been 
introduced  into  the  glaze. 

The  casting  slip  is  piped  to  all  parts  of  the  casting  floor,  where  the 
ware  is  cast  in  the  usual  manner  in  plaster  molds. 

Waste-heat  driers  are  used.  After  drying,  the  Avare  is  loaded  into 
saggers  in  preparation  for  the  biscuit  firing. 

The  firing  equipment  consists  of  two  366-ft.  tunnel  kilns,  operated 
on  a  48-hour  cycle.  The  biscuit  kiln  is  fired  to  a  maximum  of  cone  11, 
which  corresponds  to  1205°  C.  on  the  recording  pyrometer.  After 
cooling  from  the  biscuit  kilns,  the  glaze  is  applied  by  dipping,  and  the 
ware  is  sent  through  the  glost  kiln,  which  is  fired  to  cone  6,  correspond- 
ing to  1150°  C.  on  the  pyrometer.  Oil  fuel,  atomized  with  air,  is  used 
on  both  kilns.     The  capacity  of  the  kilns  is  400  pieces  per  24  hours. 

Saggers  are  made  by  machine  at  the  plant.  Alberhill  bone  clay  has 
proved  a  better  structural  clay  in  sagger  manufacture  than  lone  clay. 
The  lone  clay  body  burns  too  tight,  and  losses  from  cracking  after 
repeated  use  are  high,  but  used  as  a  binder  it  is  more  or  less  satisfactory. 

The  company  has  recently  developed  a  line  of  crystalline-glaze  art- 
ware,  and  many  attractive  shapes  and  color  schemes  are  being  produced. 

The  plant  has  a  well-equipped  laboratory,  and  through  careful  tech- 
nical control  the  products  of  the  plant  are  of  remarkably  high  quality 
and  free  from  defects.     The  plant  employs  150  men. 

Bibl    (Clay   resources   of   San   Mateo    Count v)  :  State   Min.   Bur. 
Bull.  38,  pp.  228-221),  255;  Prel.  Kept.  7,  pp.  95-96. 


(LAY  RESOURt'ES  AND  CERAMIC  INDUSTRY  217 

SANTA    BARBARA   COUNTY. 
General    Features.' 

Santa  Barbara  County  consists  of  2740  square  miles,  includino;  the 
islands  of  San  Mi<ruel.  Santa  Kosa,  and  Santa  Cruz,  which  are  located 
twenty  miles  off  the  coast.  It  is  bounded  on  the  north  by  San  Luis 
Obispo  County,  on  the  east  by  Ventura  County,  on  the  south  by  the 
Santa  Barbara  Cliannel,  and  on  the  west  by  the  Pacific  Ocean. 

The  population,  accnrdinp-  to  the  census  of  1920,  was  41,097,  and  is 
now  estimated  as  over  50,000.  The  city  of  Santa  Barbara,  the  county 
seat,  with  a  population  of  over  30,000,  lies  on  the  shores  of  the  channel. 
Santa  Maria  is  the  second  community  in  Santa  Barbara  County  and 
has  a  population  of  over  5000. 

]\Iuch  of  Santa  Barbara  County  is  hilly  and  mountainous;  the  Santa 
Ynez,  a  low  range  of  inountains,  follows  the  trend  of  the  coast  across 
the  southei-n  jiart  of  the  county,  and  the  San  Rafael,  a  higher  range, 
strikes  througli  the  center  of  the  county  and  extends  almost  to  its  nortli- 
ern  limits.  These  mountains,  with  their  foothills  and  spurs,  impart  to 
the  whole  county-  a  rugged  and  diversified  aspect. 

The  principal  valleys  are  the  Santa  Maria,  Los  Alamos,  Lompoc, 
Santa  Ynez,  and  Cuyama.  These  fertile  areas  are  well  adapted  for  the 
growing  of  cereal  crops  and  citrus  fruits  and  cattle  raising. 

The  principal  drainage  systems  of  the  county  are  the  Santa  Maria 
and  Santa  Ynez  rivers. 

The  county  is  traversed  by  the  Southern  Pacific  railroad,  which  fol- 
lows the  coast  line,  with  branch  lines  from  Guadalupe  to  Betteravia, 
and  from  Surf  to  Lompoc.  The  Pacific  Coast  railroad,  a  narrow-gauge 
line,  runs  from  Port  llanford,  in  San  Luis  Obispo  County,  through 
Santa  IMaria  to  Los  Olivos,  with  branches  from  Santa  ]\Iaria  to  Bet- 
teravia and  Sisquoc.  Santa  ^laria  Valley  railroad  connects  with  the 
Southern  Pacific  i-ailroad  west  of  Santa  Maria  and  runs  southeast 
through  the  Santa  Maria  Valley  to  Leonard. 

The  coast  route  of  the  state  highway  enters  the  county  north  of 
Santa  Maria,  and  runs  the  length  of  the  county,  connecting  Santa  Bar- 
bara city  with  Los  Angeles  and  San  Francisco.  Different  laterals  from 
this  railway  afFnrd  trnnsjiortation  for  auto  trucks  and  stages  to  interior 
towns. 

Geology  and    Mineral    Resources. 

The  principal  geological  formations  exposed  in  Santa  Barbara  County 
are  Tertiary  shales  and  sandstones,  including  those  of  Eocene,  Miocene, 
and  Pliocene  age.  Quaternary  sediments  also  cover  a  large  area, 
especially  in  the  western  part  of  the  county.  There  is  a  small  area  of 
Franciscan  (Jurassic)  in  the  center  of  the  county,  and  a  larger  area  of 
Cretaceous  (Undifferentiated)  in  the  north-central  part  of  the  county. 

Santa  Barbara  County  owes  its  position  of  fifteenth  in  the  state  in 
regard  to  its  mineral  output  to  the  presence  of  productive  oil  fields 
within  its  boundaries.     The  total  value  of  its  mineral  production  during 

'Prom  Tucker,  W.  Burling,  Santa  Barbara  County:  State  Mineralogist's  Kept. 
XXI,  pp.   539-540,   1925. 


218  DIVISION  OP^  MINES  AND  MINING 

the  year  1026  was  $2,583,548;  of  this  amount  the  value  of  natural  gas 
and  petroleum  was  $1,772,678. 

Among  its  mineral  resources,  both  developed  and  undeveloped,  are : 
Asphalt  and  bituminoas  roek,  barytes,  brick,  chromite,  copper,  diato- 
maceous  earth,  gilsonite.  jiold,  gypsum,  limestone  and  lime,  manganese, 
mineral  water,  natural  gas,  oil  shale,  petroleum,  sandstone  and  the 
stone  industry. 

Clay   Resources. 

Xo  commercial  deposits  of  high-grade  clays  have  been  found  in  the 
county.  Common  clay  is  fairly  abundant,  and  several  brick  yards  and 
a  roofing  tile  plant  are  in  operation. 

AnguJo  Tile  Company,  Plant  No.  1.  R.  F.  Angulo  and  Sons,  owners. 
Address  P.  0.  Box  128,  Santa  Barbara.  This  company  has  two  plants 
for  the  manufacture  of  hand-made  roofing  tile  and  terrace  tile.  Plant 
Xo.  1  is  on  Central  Avenue,  between  Modoc  Road  and  the  state  highway, 
Santa  Barbara,  and  Plant  Xo.  2  is  at  Reseda,  Los  Angeles  County  (see 
under  Los  Aneeles  Countv.  At  Plant  No.  2  a  local  surface  clav  is 
mined  from  an  area  immediately  adjoining  the  ]>lant.  The  plant  is 
equipped  with  three  kilns,  fired  with  oil. 

L.  L.  Brentner.  Carpinteria.  The  property  is  west  of  the  coast 
highway,  14  miles  north  of  Ventura,  and  four  miles  south  of  Carpin- 
teria. Ten  acres  were  at  one  time  under  lease  to  the  Builder's  Supply 
Company  of  Santa  Barbara,  who  operated  a  plant  for  the  manufacture 
of  common  brick.  It  is  understood  that  the  proi)erty  is  now  idle  (1927). 
The  clay  beds  are  nearly  vertical,  have  an  east-west  strike,  and  are 
about  200  feet  thick.  The  material  is  a  light-colored  thin-bedded  shale, 
with  quartz,  limestone,  and  sandstone  boulders,  which  were  i)artly 
removed  by  screening.  A  drag-line  scrajjcr  was  used  for  mining.  The 
plant  is  equipped  with  crushing  machinery  to  deliver  a  20-mesh  product 
to  the  brick  plant,  which  consists  of  a  14-ft.  pug-mill  and  an  auger 
machine,  with  a  wire  cutter.  The  brick  were  dried  in  the  open  and 
fired  in  oil-fired  field  kilns. 

Sample  Xo.  3  was  taken  for  testing,  the  results  of  which  are  on  page 
348.    The  material  is  not  of  good  quality  for  the  manufacture  of  brick. 

Bibl:  State  Mineralogist's  Rept.  XXI,  pp.  546-547,  1925. 


Muengenherg  and  WhitiJcer.  R.  ]\Iuengenberg  and  E.  H.  Whitiker, 
of  230  de  la  Guerra  Street,  Santa  Barbara,  are  operating  two  of  the 
brick  yards  formerly  opei-ated  by  the  Builder's  Supply  Company  in 
Santa  Barbara  and  Montecito. 

The  Santa  Barbara  plant,  formerly  the  Parker  Brick  Company,  is 
on  West  Montecito  Street,  one-half  mile  from  the  Southern  Pacific 
railroad  tracks.  Common  red  brick,  hollow  building  tile,  and  drain  tile 
are  made  from  clays  obtained  from  ]iits  on  the  i)lant  site  and  from 
other  sources  in  the  vicinity.  The  stiff-mud  process  is  used.  The  ware 
is  dried  in  the  open,  and  fired  in  oil-fired  field  kilns.  Samj^le  Xo.  1 
Avas  taken  for  test,  the  results  of  which  are  on  ])age  338.  Tlie  sample 
was  taken  from  the  i)ug-mill,  and  is  typical  of  the  class  of  material 
available  in  the  district,  and  for  which  the  plant  ha.s  been  designed, 
rather  than  being  rej^resentative  of  a  specific  clay  bank. 

The  Toro  Canyon  plant,  formerly  the  Toro  Canyon  Brick  and  Tile 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  219 

Company,  is  in  Torn  Canyon,  near  IMontecito.  There  is  an  anii)U'  sup- 
ply of  plastic  clay,  interinintrled  with  blocks  of  soft,  yellow  sandstone. 
The  clay  is  mined  from  a  sliallow  side-hill  open  cut  with  tractors  and 
scrapers.  Connnon  red  brick,  hollow  buildinji'  tile,  and  roofin**'  tile  are 
made.  Drying'  is  done  under  sheds  and  in  the  open,  and  oil-fired  field 
kilns  are  used  for  firing.     Sample  No.  2  (see  p.  338)  was  taken. 

Bibl:  State  Mineralogist's  Repts.  XV,  p.  735;  XXI,  pp.  546-547. 

Bull.  38,  p.  25(i.    Prel.  Kept.  7,  p.  96. 

SANTA   CLARA  COUNTY. 
General    Features. 

Santa  Clara  County  lies  in  the  west-central  portion  of  the  state.  Tt 
is  bounded  on  the  north  by  San  ^lateo  and  Alameda  counties,  on  the 
east  by  Stanislaus  aiul  Pierced,  on  the  south  by  San  F)enito,  and  on  the 
west  by  Santa  Cruz  and  San  ^lateo.  The  area  of  the  county  is  1328 
square  miles,  and  the  jiopulation  is  100,588  (1920  census).  The  prin- 
cii)al  towns  are  San  Jose,  Palo  Alto,  Santa  Clara,  and  Gilroy,  all  of 
which  lie  in  a  broad  valley  between  two  ))arallel  ranges  of  the  Coast 
Range  system  of  mountains.  This  valley  is  noted  as  one  of  the  most 
productive  fruit-growing  sections  in  California. 

The  g-eological  formations  that  are  most  widespread  in  the  county  are 
Quaternary  sediments  in  the  valleys,  and  Franciscan  (Jurassic), 
Cretaceous,  Pliocene,  and  Pliocene  formations  in  the  mountains. 

The  New  Almaden  district,  about  15  miles  south  of  San  Jose,  was  for 
many  years  famous  as  a  (quicksilver  producer,  but  the  production  has 
declined  in  recent  yeai's  owing  to  the  exhaustion  of  the  mines.  The 
following'  mineral  products  are  produced  commercially :  brick,  clay, 
limestone,  magnesite,  mineral  water,  natural  gas,  petroleum,  quicksilver, 
and  miscellaneous  .stone.  Of  these  miscellaneous  stone,  brick,  and 
quicksilver  are  the  most  important,  in  the  order  given.  Occurrences 
of  chromite,  manganese,  and  soapstone  are  known. 

Clay    Resources. 

No  commercial  dei)osits  of  high-grade  clays  are  known  in  the  county. 
Common  clays  suitable  for  the  manufacture  of  brick  and  tile  are  abund- 
ant throughout  the  valley  i)ortions  of  the  county.  On  account  of 
favorable  manufacturing  and  marketing  conditions,  a  number  of  clay- 
working  plants  have  been  established  in  and  near  San  Jose  and  Santa 
Clara.  Some  of  these  ]ilants  use  common  clay  from  extensive  deposits 
along  Coyote  Creek  within  the  city  limits  of  San  Jose.  The  clay  bed 
is  from  15  to  20  feet  thick. 

Garden  City  Pottery  Company.^  H.  ]M.  Stammer,  president;  D. 
Raymond,  vice  president ;  N.  J.  Mahan,  secretary.  Office  and  plant  at 
560  N.  Sixth  Street,  San  Jose.  This  com])any  was  established  in 
1904,  under  the  name  of  the  Garden  City  Pottery.  The  products  of 
the  plant  are  flower  pots  and  stoneware.  Lincoln  clay  is  used  for  the 
strneware,  and  a  local  red  clay,  from  Coyote  Creek,  is  used  for  flower 
])ot.s.  The  stoneware  mix  is  prepared  by  grinding,  washing,  and  filter- 
I)ressing-,  followed  by  pugging.  After  shaping,  the  ware  is  dried  in 
steam-heated  drying;  rooms  for  a  period  of  three  or  four  days. 


^Data  obtained  by  D.   R.   Irving,   Stanford  University. 


220  DIVISION  OF  MINES  AND  MINING 

Firing:  is  done  in  four  round  down-draft  kilns.  Two  of  the  kilns  are 
20  feet,  and  the  other  two  are  18  feet  in  diameter.  They  are  fired 
with  oil,  which  is  atomized  with  steam.  The  stoneware  is  fired  to 
2200°  F.  (about  cone  5)  in  72  hours,  and  the  flower  pots  are  fired  to 
1800°  F.  (about  cone  07)  in  48  hours. 

The  plant  operates  throughout  the  year  and  employs  30  men. 
Bibl :  State  Min.  Bur.  Bull.  38,  p.  229 ;  Prel.  Rept.  No.  7,  p.  96. 

Gilroy  Brick  and  Tile  Company.  Chas.  Bolting,  Gilroy.  Mr.  Bolting 
built  and  operated  a  small  common  brick  plant  for  a  few  years  on  his 
ranch  about  one  mile  north  of  Gilroy,  using  a  clay  shale  obtained  from 
a  deposit  on  the  Redwood  Retreat  Road,  about  eight  miles  from  Gilroy. 
The  plant  was  not  commercially  profitable,  and  has  been  partly 
dismantled. 

Kartscho'ke  Clay  Products  Compan]i.  G.  Kartschoke,  president  and 
manager.  Plant  at  1098  S.  Third  Street,  San  Jose.  The  principal 
products  of  the  plant  are  sewer  pipe,  flue  lining,  and  patent  chimney 
pipe.  The  plant  is  also  equipped  to  make  machine-made  roofing  tile. 
The  clays  are  obtained  from  banks  along  Coyote  Creek,  with  the  addi- 
tion of  some  clay  that  is  purchased  from  the  Yarn  deposit  in  Amador 
County. 

The  clays  are  ground  in  a  dry  pan  and  elevated  to  a  double-shaft  pug- 
mill,  from  which  the  mix  passes  to  an  American  sewer  pipe  press. 
Drying  is  done  in  a  building  which  is  heated  by  steam  during  the  win- 
ter.    Four  to  five  days  are  usually  required  for  drying. 

The  ware  is  fired  in  three  oil-fired  round  down-draft  kilns,  22  feet, 
26  feet  and  28  feet  in  diameter,  respectively.  Cone  2  (1165°  C.)  is 
reached  in  80  to  90  hours,  the  entire  cycle,  including  setting  and  draw- 
ing, requiring  about  two  weeks. 

Bibl:  State  Mineralogist's  Rept.  XIII,  p.  618;  State  Min.  Bur. 
Prel.  Rept.  7,  p.  97. 

J.  B.  King,  of  Skyland,  P.  0.,  Wrights  Station  (Santa  Cruz  County). 
It  is  reported  that  there  is  a  "fine,  large  deposit  of  pottery  clay"  on 
this  property.  No  investigation  was  made.  As  the  locality  is  relatively 
inaccessible,  near  the  summit  of  the  Santa  Cruz  Mountains,  the  clay 
would  need  to  be  of  exceptional  quality  to  be  of  commercial  importance. 

Piatt's  Premier  Porcelain,  Incorporated.'^  H.  D.  Melvin,  president; 
A.  A.  Baker,  vice  president ;  N.  E.  Wretman,  secretary.  Office  and 
plant  on  Lafayette  Street,  Santa  Clara.  This  company  makes  sanitary 
porcelain  from  a  mixture  of  English  china  and  ball  clays,  Arizona 
feldspar,  and  California  silica.  The  feldspar  and  flint  are  received  at 
the  plant  in  pulverized  form.  The  mixes  are  prepared  by  blunging  and 
filter-pressing.  The  ware  is  shaped  by  the  casting  process,  although 
hand-pressing  was  formerly  used,  and  is  dried  in  steam-heated  rooms 
for  a  period  of  one  week.  Three  16-ft.  round  ui)-draft  ('bottle')  kilns 
are  used  for  firing.  These  use  oil  fuel,  atomized  with  steam.  The  biscuit 
ware  is  fired  to  cone  9  (1250°  C.)  in  36  hours,  and  the  glost  ware  is  fired 
to  cone  8  (1225°  C.)  in  30  hours.  Tlie  jdant  was  idle  during  1927,  but 
expected  to  resume  operations  early  in  1928. 

•  Data  obtained  by  D.  R.  Irving,   Stanford  Univer.sity. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  221 

EcmiUard  Brick  Company.  C.  Kciuillard,  president ;  R.  C.  Giroux, 
secretary.  Office,  Xi2  Plielan  r>iiil(liii«i-,  San  Francisco.  This  company 
has  operated  a  brickyard  at  IMcasanton,  Alameda  County,  for  many 
years,  and  has  recently  established  a  plant  in  San  Jose,  on  Storey  Koad, 
on  the  eastern  edge  of  town.  Common  red  brick  are  made  from  a 
local  clay,  nsin«i-  open  field  kilns  for  firing.  The  plant  is  operated  for 
about  eight  months  during  the  year. 

San  Jose  Brick  and  Tile  Company.  J.  J.  Jainiesen,  president;  R.  L. 
Richards,  secretary-treasurer.  Address  P.  0.  Box  274,  San  Jose.  The 
plant  is  on  Fruitvale  Avenue,  and  the  property  comprises  85  acres. 
Common  red  brick  is  manufactured.  The  clay  deposit  consists  of  a 
30-ft.  bed  of  red-brown  plastic  clay  overlain  by  three  to  five  feet  of  soil. 
The  clay  is  mined  and  clelivered  to  the  plant  by  a  drag-line  scraper. 

The  plant  is  equipped  with  an  E.  M.  Freeze  K-B  brick  machine, 
which  has  a  capacity  of  75,000  brick  per  day  and  is  driven  by  a  150-h.p. 
electric  motor.  An  industrial  ear  system  is  used  in  the  drying  and 
kiln  yard.  Diying  in  open  racks  requires  from  seven  to  eight  days. 
One  round  down-draft  kiln  and  two  down-draft  continuous  kilns  are 
used  for  firing.  Coal  screenings  are  used  as  fuel.  The  firing  schedule 
of  the  continuous  kilns  is  as  follows:  three  days  Avater  smoking,  four 
days  firing  and  ten  days  cooling. 

The  plant  is  usually  operated  for  nine  months  of  the  year,  employing 
50  men,  and  using  345  h.p.  of  electric  power.  The  average  fuel  con- 
sumption is  300  lb.  of  coal  per  thousand  brick. 

San  Jose  Tile  Companij.  A  partnership,  consisting  of  L.  W.  Austin, 
D.  W.  Wallace,  L.  F.  Wallace,  W.  D.  Rice,  and  L.  II.  Bruns.  The  plant 
is  at  333  S.  Eighteenth  Street,  San  Jose,  on  the  banks  of  Coyote  Creek. 
Hand-made  floor,  wall,  and  mantel  tile  are  manufactured,  using  a  red- 
burned  body  consisting  largely  of  clay  from  the  Natoma  Clay  Comi)any 
in  Sacramento  County.  Local  clay  from  Coyote  Creek  and  some  Lin- 
coln and  lone  materials  are  used  to  a  certain  extent.  The  equipment 
consists  of  a  disintegrator  and  pug-mill,  and  a  rectangular  kiln,  burn- 
ing oil.  The  kiln  is  equipped  with  a  pyrometer.  The  firing  period  is 
from  40  to  48  hours,  finishing  at  cone  5  (1180°  C),  or  higher. 

An  excellent  market  has  been  established  for  the  ware,  and  the  plant 
is  expected  to  grow  rapidly. 

8  &  S  Tile  Company.  A.  L.  Solon  and  F.  P.  Schemmel,  owners. 
Office  and  plant  at  1881  S.  First  Street,  San  Jose.  This  company 
specializes  in  the  manufacture  of  decorative  tile,  both  glazed  and 
unglazed,  from  a  huff,  or  red-colored  body.  Local  clay  from  Coyote 
Creek  is  used  in  conjunction  with  Lincoln  clay  and  lone  sand.  Biscuit 
re.iects  and  kiln  dirt  are  used  as  grog. 

The  clays  are  mixed  in  batches  on  the  floor,  fed  to  a  Jeffrey  swing- 
hammer  mill,  and  elevated  to  a  bin,  from  which  they  are  fed  by  a  disc 
feeder  to  a  pug-mill.  A  INIuller  auger  is  used  for  shaping  all  plain  tile, 
whereas  fancy  tile  is  hand-pressed  in  plaster  molds.  Some  dry-pressed 
tile  are  made  at  times.  A  specially  designed  waste-heat  drier  is  used. 
To  secure  partial  humidification,  the  drier  is  arranged  so  that  the  hot 
air  can  be  retained  in  closed  circuit.  Drying  requires  three  days.  Two 
oil-fired  round  kilns  are  used.  These  are  18  and  22  feet  in  diameter, 
respectively.     They  are  fired  to  cone  2  (1135°  C.)  in  48  hours.     Cool- 


222  DIVISION  OP  MINES  AND  MINING 

ing:  requires  four  days.  Both  kilns  are  ecinipped  Avitli  base-metal 
thermocouples.  All  j^lazed  ware  is  biscuited  first,  then  .ulazed.  About 
eight  men  and  six  women  are  employed. 

SANTA   CRUZ  COUNTY. 
General    Features.' 

8anta  Cruz  County  borders  on  ]\Ionterey  Bay  and  the  Pacific  Ocean, 
south  of  San  Mateo  County,  and  north  of  ^Monterey  County.  Its  area 
is  435  square  miles,  and  the  population  is  26,269  (1920  census).  The 
oreater  part  of  the  county  is  rugged  and  mountainous. 

The  geology  of  most  of  the  county  is  described  in  U.  S.  Geological 
Survey,  Santa  Cruz  Folio,  No.  163,  by  J.  C.  Branner,  J.  F.  Newsom, 
and  Ralph  Arnold.  The  principal  sedimentary  formations  are  of 
Miocene  and  Pliocene  age.  There  is  an  extensive  area  of  quartz-diorite, 
and  smaller  areas  of  metamorphic  schist,  marble,  and  limestone. 

The  mineral  production  of  the  county  includes  cement,  lime,  lime- 
stone, and  miscellaneous  stone,  and  bituminous  rock. 

Clay   Resources. 

Common  brick  clays  occur  along  the  San  Lorenzo  River  and  at  other 
points.  In  the  early  nineties,  two  brickyards  were  in  operation  near 
Santa  Cruz,  but  these  have  long  since  been  dismantled.  Clay  is  being 
mined  at  Tank  Siding,  1.8  miles  southwest  of  Glenwood,  and  at  Daven- 
port, for  use  in  the  manufacture  of  cement  at  the  j^lant  of  the  Santa 
Cruz  Portland  Cement  Company,  at  Davenjjort. 

Bibl:  State  Mineralogist's  Repts.  X,  p.  625;  XII,  p.  383;  XIII,  p. 
619;  XVII,  p.  234;  XXII,  pp.  78-79.  Prel.  Rejit.  No.  7,  p.  97. 

SHASTA   COUNTY. 
General   Features. 

Shasta  County  lies  at  the  northern  end  of  the  Sacramento  Valley. 
Redding,  the  county  seat,  is  on  the  Shasta  line  of  the  Southern  Pacific 
Railroad,  175  miles  north  of  Sacramento,  and  is  the  principal  rail- 
road and  supply  point  for  Shasta  and  Trinity  counties.  The  Pacific 
highway  connecting  California  anfl  Oregon,  traverses  the  county  in 
a  north  and  south  direction,  paralleling  the  Southern  Pacific  railroad 
in  the  Sacramento  River  Canyon. 

The  area  of  Shasta  County  is  3858  square  miles  and  the  population 
in  1920  was  13,311.  The  southern  ])ortion  of  the  county  adjacent  to 
the  Sacramento  River  is  open  and  rolling,  and  is  devoted  to  farming 
and  stock  raising.  The  northern  and  western  ])ortions  of  the  county 
are  mountainous,  and  the  eastern  ])ortion  is  a  succession  of  rising 
plateaus  covered  by  recent  volcanic  flows.  ]\Iost  of  the  important 
mineral  deposits  of  the  county  are  confined  to  the  western  half.  The 
Pit  River,  which  joins  the  Sacramento  River  near  Redding,  is  an  import- 
ant source  of  hydro-electric  ]iower.  Timber  is  an  important  resource 
of  the  county,  especially  in  the  eastern  portion. 

Shasta  County  is  characterized  by  the  variety  of  its  geologic  forma- 
tions, and  the  diversity  of  its  mineral  resources.     Copper,  gold,  zinc 

'See  Laizure,  C.  McK.,  Santa  Cruz  County  :  State  Min.  Bur.  Rept.  XXII,  pp.  68-93, 
1926. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  223 

and  iron  aro  the  principal  metals  thai  liave  been  produced  in  the 
county.  The  limestone  resources  are  very  extensive,  but  to  date  have 
not  been  exjiloited  on  a  lar«re  scale.  Ext(Misive  beds  of  low-«»rade 
lij,niile  occur  in  the  central  part  of  the  county.  These  have  been 
investigated  many  times  in  the  past,  and  an  attempt  is  now  being  made 
to  place  them  upon  a  sound  commercial  basis. 

Clay  Resources. 

Tliere  is  at  present  no  clay  industry  in  the  county.  At  various  times 
in  the  past,  brick  yards  have  been  operated  at  Redding  and  Anderson, 
to  supply  local  needs,  but  these  have  been  idle  for  many  years.  There 
is  an  abundant  sui)ply  of  clay  and  silt  suitable  for  common-brick 
manufacture  in  the  flood  plain  of  the  Sacramento  River  south  of 
Redding,  and  along  other  streams  in  the  county. 

No  commercial  deposits  of  high-grade  clays  have  yet  been  discovered 
in  the  county.  It  is  possible  that  with  the  serious  development  of  the 
lignite  properties  northeast  of  Oak  Run,  mainly  in  T.  33  N.,  R.  1  W., 
M.  D.  M.,  refractory  clays  may  be  encountered,  as  the  lignites  occur  in 
the  lone  formation,  which  is  the  important  source  of  terra  cotta  and 
fireclays  in  I^lacer  and  Anuulor  counties.  A  small  samjile  of  micaceous 
kaolin,  slightly  tinged  with  iron,  was  supplied  by  Mr.  I.  J.  Johnson, 
of  the  Johnson  Iron  Works,  Redding,  but  no  data  could  be  secured  as 
to  the  source  of  this  nuitcrial,  excei)t  that  it  was  found  on  a  property 
some  20  miles  northeast  of  Palo  Cedro. 

For  convenience  of  reference,  the  following  descrii)tions  of  common- 
brick  clay  deposits  are  abstracted  from  previous  publications  of  the 
Bureau : 

State  Mineralgist's  Report  XXII,  p.  131,  1926;  Prel.  Rept.  No.  7, 
p.  98,  1920. 

Holt  and  Gregg,  J.  N.  Gregg,  president,  Kennett.  A  brick  j)lant 
was  formerly  operated  at  Anderson,  in  Sec.  17,  T.  30  N.,  R.  4  W., 
M.  D.  ]\I.     The  deposit  was  15  feet  thick. 

Block  29,  Bedding  Grant,  1]  miles  south  of  Redding.  Clay  bed  six 
feet  thick.    A  brick  kiln  was  operated  here  many  years  ago. 

Bedding  Brick  and  Tile  Compamj  f(n-mer]y  ojierated  a  dei)osit  on  40 
acres  in  Sec.  19,  T.  31  N.,  R.  5  W.,  M.  D.  M.,  and  made  brick  in  small 
kiln  at  Redding. 

Bedding  Homestead  Deposit  is  on  the  Sacramento  River  east  of 
Cottonwood.  Deposit  is  a  mile  long  by  one-fourth  mile  wide  and 
contains  30  feet  of  clay,  covered  by  15  feet  of  sand  and  gravel.  Unde- 
veloped.    No  recent  information  available. 

Southern  Pacific  Company  owns  an  undeveloped  clay  deposit  in 
Sec.  19,  T.  32  N.,  R.  4  W.,  M.  D.  M. 

In  addition  to  the  foregoing,  a  deposit  of  fireclay  is  reported  in  Sec. 
24,  (34?)  T.  34  N.,  R.  5  W.,  M.  D.  M.,  that  was  at  one  time  operated 
by  Holt  and  Gregg  for  use  as  kiln  lining.  No  recent  information  since 
the  report  of  1920. 


224  DIVISION  OP  MINES  AND  MINING 

SISKIYOU    COUNTY. 
General  Features. 

Siskiyou  County  borders  on  the  state  of  Oregon  in  a  sparsely-settled 
mountainous  portion  of  California.  The  total  area  of  the  county  is 
6256  square  miles,  and  the  population  (1920)  is  18,500.  The  county 
is  traversed  by  the  Sliasta  line  of  the  Southern  Pacific  railroad.  The 
principal  industries  of  the  county  are  lumbering,  stock-raising  and 
farming.  The  mineral  industry  of  the  county  is  not  at  i)resent  of 
great  importance,  although  in  the  past  the  county  has  been  celebrated 
for  its  placer  mines,  and  during  the  late  war  it  was  an  important  source 
of  chromite.  The  geology  and  mineral  resources  of  the  county  have 
been  discussed  in  a  recent  report.^ 

Clay   Resources. 

On  account  of  the  remoteness  of  the  county  from  the  centers  of  popu- 
lation and  the  small  population  within  the  county  itself,  none  but 
exceptionally  high-grade  clay  deposits  could  have  commercial  value. 
A  deposit  of  'pottery  clay'  16  ft.  thick  has  been  reported-  in  Sec.  8, 
T.  43  N.,  R.  6  W.,  near  Gazelle.  A  careful  search  for  this  deposit  was 
made  in  August,  1925,  and  local  inhabitants  were  questioned  concern- 
ing it,  but  no  knowledge  of  such  a  deposit  could  be  obtained.  The 
report  probably  refers  to  a  deposit  of  yellow  plastic  clay  that  occurs  on 
the  pro})erty.  A  de])osit  of  fireclay  in  the  roof  of  a  coal  mine  in 
Sec.  26,  T.  46  N.,  R.  6  W,,  has  also  been  reported  ^  but  could  not  be 
verified.     The  coal  mine  referred  to  is  now  inaccessible. 

Common  brick  clays  occur  in  irregular  alluvial  deposits  at  various 
places  in  the  county.  Some  of  these,  near  Yreka,  Etna  Mills,  and  Fort 
Jones  have  been  used  in  the  past  for  producing  brick  for  local  use 
during  the  early  construction  periods  of  the  larger  towns  in  the  county. 
None  of  the  brick  yards  have  been  operated  for  many  years,  and  have 
long  since  been  dismantled.  If  at  any  time  in  the  future  it  should 
become  necessary  to  manufacture  small  quantities  of  red  brick  in  the 
county,  enough  clay  of  satisfactory  quality  could  probably  be  found, 
but  it  is  unlikeh'  that  large  deposits  of  uniformly  good  material  will  be 
encountered. 

For  convenience  of  reference,  the  previous  reports  of  the  bureau  on 
common  clay  deposits  in  Siskiyou  County  are  summarized  below,  but 
as  these  reports  are  over  20  years  old,  the  names  of  the  men  who  were 
formerly  associated  with  the  deposits  are  omitted  here,  as  few  of  them 
can  now  be  found. 

T.  43  N.,  R.  9  W.,  M.  D.  M.  Surface  clay  deposits  were  reported  in 
Sec.  2,  11,  21  and  32,  in  the  vicinity  of  Fort  Jones,  Green  view,  and 
Etna.     These  clays  have  been  used  for  brick  making. 

Sec.  27,  T.  45  N.,  R.  7  W.  Bricks  were  once  manufactured  from  a 
reddish  clay  near  Yreka. 

Near  Montague  a  small  quantity  of  brick  clay  has  been  found. 

Bibl :  Cal.  State  Min.  Bur.  Bull.  38,  p.  230  and  257,  1906 ;  Prel. 
Rept.  No.  7,  p.  98,  1920  (a  copy  of  the  material  in  Bull.  38). 

'  state  Mineralogist's  Report  XXI,   jip.    413-498.      1925. 
=  Prel.  Rept.  No.  7,  p.  99. 
'  Op.  cit.,  p.  98. 


CLAY  RESOURCES  AND  CERAMi:'  INDUSTRY  225 

SOLANO   COUNTY. 
General    Features.' 

Solano  County  i-adiates  in  a  northeasterly  direction  from  San  Pablo 
Bay,  an  arm  of  San  Francisco  Bay.  Its  area  is  822  square  miles,  and 
the  jiopulation  is  40,602  (1920  census).  About  80  per  cent  of  the 
land  is  arable  and  the  balance  is  mountainous.  Cretaceous  and  Ter- 
tiary sediments,  and  late  Tertiary  (probable)  lavas  are  found  in  the 
mountainous  portion  of  the  county.  The  rest  of  the  county  is  covered 
with  Recent  alluvium. 

Among  the  mineral  resources  of  Solano  County  are  cement,  clay, 
fuller's  earth,  limestone,  mineral  water,  natural  ji'as,  onyx,  quicksilver, 
salt  and  miscellaneous  stone,  llecent  production  has  been  confined  to 
cement,  miscellaneous  stone,  mineral  water,  onyx  and  travertine.  The 
only  cement  plant  in  the  county  was  closed  down  in  November,  1927, 
aiul  is  available  as  a  stand-by  plant. 

Clay    Resources. 

Common  brick  clays  are  abundant  in  the  argicultural  section  of  the 
county.  A  number  of  clay-working  plants,  including  a  pottery  at 
Renicia  and  brick  and  tile  plants  at  Vallcjo,  were  active  a  number  of 
years  ago. 

Steiger  Brick  and  Tile  Company  (formerly  the  Vallejo  Brick  and 
Tile  Company).  Plant  two  miles  northwest  of  the  center  of  Vallejo. 
This  is  the  latest  attempt  to  operate  a  bricln^ard  in  the  county,  and 
operations  were  discontinued  in  1923.  The  plant  is  equipped  for  the 
manufacture  of  brick  and  hollow  tile.  The  clay  deposit  is  a  yellow 
siiale,  an  analysis  of  which  is  reported  by  Laizure-  as  follows: 

Loss  on  ignition 8.03% 

Silica     57.83% 

Alumina    19.52% 

Iron  oxides    7.46% 

Calcium  oxide 1.24% 

Magnesium  oxide ^ 2.06% 

Alkalies    (by   difference)    3.86% 

100.00% 

Clav  from  a  bank  at  the  base  of  the  hills  near  Goodvear  Station  was 
utilized  about  20  years  ago  in  a  pottery. 

Bibl :  State  Mineralogist's  Repts.  VIII,  p.  631 ;  XIII,  p.  619  ;  XIV, 
]).  300;  XXIll,  pp.  204-205.  State  Min.  Bur.  Bull.  38,  p.  258. 
Prel.  Rept.  No.  7,  p.  99. 

SONOMA   COUNTY. 
General    Features.' 

Sonoma  County  is  situated  north  of  IMarin  County  and  San  Pablo 
Bay,  extending  eastward  from  the  Pacific  Ocean,  which  it  borders  for 
50  miles,  to  the  crest  of  the  Coast  Range,  which  forms  the  boundary 
.separating  it  on  the  east  from  Lake  and  Napa  counties.  Mendocino 
County  bounds  it  on  the  north.     The  land  area  of  the  county  is  1577 

'  See  Laizure,  C.  McK.,  Solano  County :  State  Mineralogist's  Rept.  XXIII,  pp. 
203-213,   1927. 

=  Op.  cit.,  p.  204. 

3  From  Laizure,  C.  McK.,  Sonoma  County :  State  Mineralogist's  Rept.  XXII,  pp. 
327-329,   1926. 

15—54979 


226  DIVISION  OF  MINES  AND  MINING 

square  miles,  and  tlie  poi)ulation  is  51,990  (1920  census).  Tliere  are 
no  ini{)rove(l  harbors  on  the  coast  side,  but  water  shii)i)ing  facilities  are 
available  in  the  southern  portion,  which  borders  the  bay.  The  North- 
western Pacific  railroad  traverses  the  county  from  south  to  north 
throufih  the  central  valley,  with  branch  lines  into  Sonoma  Valley,  to 
Sebastopol  and  to  the  Russian  River  region  around  Guerneville,  Dun- 
can Mills  and  Cazadero.  A  narrow-gauge  branch  also  extends  from 
Marin  County  northward  through  Valley  Ford  to  ]\Ionte  Rio  in  the 
western  part.  A  line  of  the  Southern  Pacific  railroad  from  Xapa 
Junction  in  Xapa  County  traverses  the  Sonoma  Valley  and  terminates 
at  Santa  Rosa.  The  Petaluma  and  Santa  Rosa  electric  system  also  gives 
service  to  the  southern  portion  of  the  county.  The  paved  'Redwood 
Highway'  of  the  state  system  closely  i)arallels  the  Northwestern  Pacific 
railroad  through  the  county.  Its  main  laterals  are  also  paved  or  well- 
kept  graveled  roads. 

The  county  produces  a  great  variety  of  agricultural  products,  and 
dairying  and  stock-raising  are  important  sources  of  wealth.  Its  min- 
eral deposits  have  been  exploited  more  or  less  continuously  since  the 
sixties,  and  although  it  can  scarcely  be  classified  as  a  'mining'  county, 
metals  and  nonmetallic  minerals  exceeding  $11,000,000  in  value  have 
been  produced  to  date.     Its  resources  are  still  far  from  exhausted. 

Many  health-giving  mineral  springs  are  found  here,  and  its  resorts 
have  made  the  county  one  of  the  favorite  playgrounds  of  central 
California. 

Situated  in  the  midst  of  the  Coast  Range,  its  topographic  features 
include  level  valleys,  Ioav  rolling  hills  and  rugged  mountains,  with  deep- 
cut  canyons.  The  drainage  of  the  southern  portion  is  to  the  bay, 
while  that  of  the  northern  two-thirds  is  to  the  Pacific  Ocean,  chiefly  by 
the  Russian  River  and  its  tributaries.  The  main  valley  area,  beginning 
at  the  bay,  extends  through  the  center  of  the  county  for  about  60  miles, 
with  an  average  width  of  25  miles,  but  narrowing  toward  the  northern 
end.  Numerous  smaller  valleys  separate  the  lesser  spurs  and  ridges  of 
the  main  range. 


"^f?^ 


Geology. 

Sonoma  County  is  not  covered  by  any  of  the  Ignited  States  Geological 
Survey  Folios,  and  the  geologic  literature  on  this  area  is  fragmentary. 
The  general  geology  has  been  described  in  part  by  Osmont,^  and  bj' 
Vander  Leek,-  in  its  relation  to  possible  oil  production.  The  geology 
of  the  quicksilver  ore  deposits  has  also  been  covered  in  considerable 
detail  by  various  writers. 

As  shown  on  the  State  Mining  Bureau's  geological  map  of  the  state, 
the  Franciscan  rocks  of  the  Coast  Range  cover  probably  three-fourths 
of  Sonoma  County,  extending  in  a  broad  belt  from  the  ^larin  County 
line  northwesterly  the  entire  length  of  the  county  and  beyond.  This 
belt  of  metamorphic  rocks  widens  toward  the  north.  It  consists  mainly 
of  sandstone,  with  smaller  amounts  of  limestone,  slates,  cherts,  schist, 
and  much  serpentine.  Bordering  the  coast  from  Salmon  Creek  north, 
is  a  belt  of  Cretaceous  sandstone  and  shale  a  few  miles  in  width.  Ter- 
tiary sedimentary  rocks  are  exposed  in   a  small  area  around  Valley 

'  Osmont,  V.  C,  A  Geological  Section  of  the  Coast  Hanges  North  of  San  Francisco : 
Bull.   Dept.  of  Geol..   University  of  California,  Vol.   4,   No.   3,  pp.   39-87. 

-  Vander  Leek.  Lawrence,  Petroleum  Resources  of  California :  State  MJn.  Bur. 
Bull.   89,  pp.   36-38. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  227 

Ford.  The  main  valley  area  is  conii)Osed  of  Quaternary  sands,  frravels, 
and  clays  aloii^'  the  Russian  River  from  Cloverdale  to  Ilealdsburg. 
These  foi-mations  nai'i-ow  at  Wiudsoi-  and  then  widen  a^ain  between 
Forestville  anil  Santa  Rosa  and  continue  south  throutrli  Sebastopol  and 
Cotati  nearly  to  Petaluma.  The  lowlands  area  around  the  mouth  of 
Petaluma  Creek  and  Sonoma  Creek  is  also  of  Quaternary  a<ie.  Most  of 
Soiumia  Valley,  the  Sonoma  Hills  and  the  area  surroundin<r  Santa 
Rosa  on  the  east  and  north  is  made  up  of  Tertiary  sediments  consisting' 
of  fine  and  medium  sands,  clay  and  shale.  Late  volcanic  lavas  cover 
a  considerable  area  in  the  nei<ih])oi'hood  of  ^Mount  St.  Helena.  They 
also  ap])ear  alon<»:  the  eastern  boundary  of  the  county,  on  the  west  side 
of  Sonoma  Valley,  and  near  Petaluma.  The  lavas  are  mainly  andesitic, 
but  in  places  jrrade  into  basalt.  Volcanic  tutfs  are  found  interbedded 
with  the  Tertiai-y  sediments  at  many  points. 

Amonji'  Sonoma  County's  mineral  resources  are  chromite,  clay,  coj)- 
per,  jii-ai)hite.  diatomite,  magnesite,  manganese,  marble,  mineral  i)aint, 
mineral  water,  (piicksilver,  and  miscellaneous  stone.  Of  these,  miscel- 
laneous stone,  (piicksilver,  mineral  water,  ]iottery  clay,  building  stone 
(tuff)  and  manganese  ore  were  produced  in  1925. 

Clay   Resources. 

There  has  been  in  the  past  a  considerable  out|)ut  of  brick  and  clay 
in  Sonoma  County,  but  no  clay-working  plants  are  active  at  present. 
Common  clays  are  sufficiently  abundant  for  all  probable  needs  of  the 
county. 

A  number  of  dejiosits  of  high-grade  clay  have  been  reported  from 
time  to  time,  but  only  one  of  these,  the  Weiss  deposit,  has  been  developed 
sufficiently  to  be  of  interest. 

Beltane.  Sample  No.  197  (see  p.  291)  was  taken  from  a  deposit  that 
is  exposed  in  a  cut  on  a  side  road,  1.3  miles  northwest  of  the  state 
highway.  The  side  road  branches  from  the  main  highway  at  a  point 
0.5  mile  north  of  Warfield  Station.  The  deposit  is  probably  near  the 
eastern  edge  of  Sec.  2,  T.  6  N.,  R.  6  W.,  M.  D.  M.,  about  two  miles  east 
of  Beltane  Station.  The  clay  is  buff-burning  and  refractory.  The 
extent  of  the  deposit  and  its  ownership  wei*e  not  determined.  This 
should  not  be  confused  with  the  Weiss  clay,  described  below,  which 
i.s  sometimes  known  as  'Beltane  clay.' 

Weiss  Deposit.  J.  II.  Weiss,  Glen  Ellen,  owner.  This  is  a  deposit 
of  white,  moderately  i)lastic,  kaolin  fireclay,  in  Sec.  3,  T.  6  N.,  R.  6  W., 
M.  D.  M..  less  than  a  mile  by  road  east  of  Beltane  station  on  the  South- 
ern Pacific.  The  de])0sit  has  been  worked  at  various  times  in  the  past, 
and  over  2000  tons  have  been  shipped  to  clay  products  manufacturers 
and  to  the  Santa  Cruz  Portland  Cement  Company  for  experimental 
purposes.  Five  cars  were  mined  and  shipped  in  June,  1925,  by  Frank 
A.  Asbury.  lessee,  of  753  Banning  Street.  Los  Angeles,  and  was  tried  in 
several  fire-brick  plants  in  the  Los  Angeles  district,  notably  by  the 
St.  Louis  Fire  Brick  and  Clay  Company. 

The  appearance  of  the  deposit  and  the  extent  of  development  work  is 
shown  in  photo  No.  66.  The  tunnel  is  said  to  be  100  feet  long,  with 
various  secondary  workings,  but  it  is  now  caved  near  the  portal.  Bor- 
ings from  the  floor  of  the  pit  are  said  to  have  encountered  clay  of 
quality  equal  to  that  exposed  in  the  workings,  to  a  depth  of  20  to  30 


228 


DIVISION  OF  MINES  AND  MINING 


feet.  There  is  a  smaller  abandoned  pit  100  feet  to  the  east,  in  which 
clay  of  a  similar  nature  is  exposed. 

The  origin  and  structural  relations  of  the  deposit  Avas  not  definitely 
determined,  but  all  available  evidence  points  to  the  theory  that  it  is  an 
alteration  in  place  of  a  flat-bodded,  fine-grained  aplitic  rock.  The 
overburden  of  several  feet  of  soil,  and  the  thick  vegetation  make  tracing 
of  the  clay  beyond  the  development  faces  difficult. 

About  400  yards  to  the  north,  and  at  a  slightly  higher  elevation,  is 
a  prominent  exposure  of  a  rock  containing  quartz  and  a  high  propor- 
tion of  feldspar.  Some  of  this  rock  has  been  mined  from  an  open  cut, 
and  the  exposed  bank  is  over  40  feet  high.  The  rock  has  been  tried  as 
a  fire-brick  grog  by  several  plants.  Near  the  top  of  the  bank,  the  rock 
is  similar  in  color  and  aggregation  to  the  clay  from  the  pit  to  the  south, 
but  is  hard  and  non-plastic.  The  more  typical  rock  from  the  lower 
part  of  the  bank  closely  resembles  a  chert.     It  is  harder  than  steel,  has 


Photo  No.   66.      Weiss  clay  deposit,  facing  noi-thwest.     Near  Glen  Ellen,   Sonunia 
County.      (Samples  No.  194  and  195.) 

a  dull  waxy  luster,  and  contains  isolated  quartz  and  altered  feldspar 
crystals,  and  scattered  discontinuous  veinlets  of  quartz. 

Sample  No.  194  is  a  general  sample  from  the  clay  pit.  Sample 
No.  195  is  a  selected  sample  of  the  whiter  clay  from  the  pit  and  from 
the  tunnel,  near  the  portal.  It  represents  from  10%  to  15%  of  the 
clay  exposed  in  the  workings.     The  test  results  are  on  page  262. 

Bibl:  State  Mineralogist's  Reports  VIII,  p.  635;  XII,  p.  384; 
XIV,  pp.  316-318;  XXII,  p.  332.  Bull.  38,  p.  258;  Pre).  Kept. 
7,  p.  99. 

STANISLAUS  COUNTY. 
General    Features.' 

Stanislaus  County  is  situated  in  the  San  Joaquin  Valley  between  San 
Joaquin  County  on  the  northwest  and  Merced  on  the  southeast.     It  is 

'  From  Laizure,  C.  McK.,  Stanislaus  County  :  State  Mineralogist's  Rept.  XXI,  pp. 
200-201.  1925. 


CLAY  RESOURCES  A.n'D  CERAIMIC  INDUSTRY  229 

bounded  on  the  northeast  by  Calaveras  and  Tuolumne  counties,  and  by 
Santa  Clara  on  the  southwest  side.  Stanislaus  County  contains  1486 
scjuare  miles,  and  its  population  is  43,557  (1920  census).  The  pfreater 
part  of  its  acreage  is  arable,  and  about  one-half  is  capable  of  irrif^ation. 
The  various  branches  of  agriculture  and  stock-raising  are  the  princi})al 
sources  of  wealth. 

The  county  extends  across  the  San  Joa(iuin  Valley  in  a  northeasterly 
direction  from  the  summit  of  the  ]\Iount  Diablo  Range  on  the  west  to 
the  foothills  of  the  Sierra  Nevadas  on  the  east.  The  central  portion  is 
composed  of  unconsolidated  sands,  gravels  and  clays.  Bordering  this 
formation  on  the  northeast,  with  the  line  of  contact  a  little  above  Oak- 
dale  and  Waterford,  is  a  belt  of  older  Tertiary  clays,  shales  and  sand- 
stones. This  Tertiary  belt  extends  to  and  comes  in  contact  with  the 
slates,  limestones  and  other  rocks  of  the  Jurassic  along  a  line  which 
closely  follows  the  northeastern  boundary  of  the  county.  On  the  south- 
west, the  low  foothills  of  the  Coast  Range  are  made  up  of  Cretaceous 
sandstones  and  shales.  The  extreme  western  portion  is  rugged  and 
composed  of  Franciscan  formations,  typical  of  the  Coast  Range ;  con- 
sisting of  altered  slates,  cherts,  massive  sandstone,  schists  and  serpen- 
tine. Deposits  of  magnesite,  manganese,  and  quicksilver  occur  in  this 
area. 

Gold  has  usually  been  the  chief  mineral  product  of  Stanislaus  County, 
but  gold  was  exceeded  in  value  in  1918-1919  b.y  manganese,  and  in 
1921-1923  by  miscellaneous  stone.  Gold,  platinum,  and  silver  are 
obtained  mainly  by  dredging.  Quicksilver  and  manganese  are  other 
metals  found  here  also.  Among  its  nonmetallic  resources  are  clay, 
ocher,  magnesite,  silica,  and  miscellaneous  stone,  including  crushed 
rock,  gravel  and  sand.  Other  minerals  occur,  but  the  deposits  in  most 
eases  have  not  been  sufficiently  developed  to  determine  their  commercial 
value. 

Clay    Resources. 

Deposits  of  common  clay,  suitable  for  the  manufactui'c  of  common 
brick,  occur  abundantly  in  the  county,  and  have  been  worked  at  various 
times  in  the  past  near  Modesto,  Grayson,  Newman,  and  Patterson,  but 
there  have  been  no  recent  operations. 

The  Craycroft  brickyard  at  Modesto  operated  between  1908  and  1916, 
but  is  now  dismantled.  In  1918  and  1919  Martin  Kelch  made  brick 
from  a  clay  deposit  having  a  maximum  thickness  of  20  feet,  on  the 
Waterford  road,  about  one  mile  ea.st  of  ]Modesto. 

No  deposits  of  high-grade  clay  are  known  to  occur  in  the  county. 
The  Cummings  Ranch  deposit,  described  below,  has  been  noted  in 
various  reports  of  the  Bureau.  On  investigation,  it  was  found  to  have 
little  or  no  commercial  value. 

Cummings  Ranch  Clay  Deposit.  On  the  property  of  J.  H.  Cum- 
mings of  Patterson,  in  Sec.  20  and  21,  T.  5  S.,  R.  7  E.,  M.  D.  M.,  is  an 
undeveloped  deposit  of  hard,  white  clay-shale.  The  deposit  occurs 
near  the  edge  of  the  foothills  west  of  Patterson,  near  the  ranch  house 
of  W.  J.  Hammond.  The  deposit  is  exposed  on  the  hillside  200  yards 
northwest  of  the  ranch  house.  The  total  distance  by  road  from  Patter- 
son is  5.9  miles.  The  shale  occurs  in  a  bed  from  10  to  15  feet  thick 
haA'ing  a  strike  of  N,  50  W.,  and  dipping  45°  NE.    The  overburden  of 


230  DIVISION  OF  MINES  AND  MINING 

shale,  sandstone  and  soil  varies  from  a  few  feet  to  over  15  feet  in 
thickness. 

Sample  No.  205  was  cut  from  a  five-foot  portion  of  the  bed  that  was 
whiter  in  color  than  the  rest.     The  test  results  are  on  page  299. 

Bibl  (Clav  resources  of  Stanislaus  County)  :  State  Mineralogist's 
Kepts.  XVII,  p.  253,  and  XXI,  pp.  204-205;  State  Min.  Bur. 
Prel.  Kept.  7,  p.  99. 

SUTTER   COUNTY. 
General    Features. 

Sutter  County  lies  north  of  Sacramento  County,  mainly  between  the 
Sacramento  and  Feather  rivers.  Its  area  is  608  square  miles,  and  the 
population  is  10,115  (1920  census). 

The  outstanding  topographic  and  geologic  feature  of  Sutter  County 
is  the  ]\Iarysville  Buttes,  which  occupy  a  circular  area  about  10  miles 
in  diameter  in  the  north-central  portion  of  the  county,  and  rise  to  a 
maximum  elevation  of  2128  feet  above  sea  level.  The  rest  of  the  county 
is  flat  and  is  covered  with  deep  alluvial  soil.  The  Buttes  consist  of  a 
core  of  andesite  with  intrusions  of  rhyolite  surrounded  by  upturned 
lone  (Eocene)  sedimentary  strata  overlain  by  andesite  tuff  and 
breccia.^  The  mineral  production  of  the  county  is  practically  nil,  and 
consists  principally  of  crushed  rock. 

Clay   Resources. 

Clay  beds  of  considerable  extent  have  been  reported  to  occur  in  the 
sedimentary  Eocene  strata  of  the  Marysville  Buttes.  A  reconnaissance 
of  the  region  was  made  by  the  author  in  August,  1925,  but  no  further 
information  could  be  obtained,  even  after  considerable  search  and  local 
inquiry. 

Bibl:  State  Mineralogist's  Kept.  XV,  p.  258;  State  Min.  Bur.  Prel. 
Kept.  No.  7,  p.  100. 

TEHAMA  COUNTY. 
General    Features. 

Tehama  County  is  in  the  upper  jiart  of  the  Sacramento  Valley.  It 
extends  east  to  the  summit  of  the  Sierras,  and  west  to  the  crest  of  the 
Coast  Range.  Its  area  is  3166  square  miles,  and  the  population  is 
2551  (1920  census).  The  Sacramento  River  flows  through  the  center  of 
the  county,  from  north  to  south. 

The  eastern  half  of  the  county  is  covered  with  sheets  of  lava,  which 
had  their  origin  from  and  around  Lassen  Peak.  The  central  part  of 
the  county  shows  an  extended  plateau  of  gravels,  sands  and  clays, 
which  extend  to  the  serpentines  and  metamorphic  rocks  of  the  Coast 
Range. 

Among  the  mineral  resources  of  Tehama  County  are  brick,  chromite, 
copper,  gold,  manganese,  marble,  mineral  water,  salt,  and  miscellaneous 
stone.  Brick  and  miscellaneous  stone  are  the  only  commercial  prod- 
ucts at  i)resent. 

'Turner,  H.  W..  and  Lindgren,  W.,  Marvsville  Folio  No.  17.  U.  S.  Geol.   Surv.,  1895. 
Lindgren.  W..  U.  S.  Geol.  Surv.  Prof.    Paper  No.   73,  pp.   2.3-25,   1911. 
Watt.s,  W.  L.,  Cal.   State  Min.  Bur.   Bull.   3,  pp.   9-10.   1894. 
Cooper,  J.  G.,  Cal.   State  Min.  Bur.  Bull   4,  pp.   36-45,   1894. 

Dickerson,  R.  E.,  Bull.  Dept.  of  Geol.,  Univ.  of  Calif.,  Vol.  7,  No.   12,  pp.  257-298; 
pi.';.   11-14,   April,   1913. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  231 

Clay   Resources. 

Common  brick  clays  are  abundant  in  the  Sacramento  Valley  portion 
of  the  county,  especially  near  the  river.  A  brickyard  has  been  operat- 
in<r  intermittently  at  Red  l>lutt'  for  manv  years. 

Banks  of  clay  of  fine  quality  are  reported  in  the  Flounwij  di.strict.' 
Plournoy  is  in  T.  24  N.,  R.  5  W.,  about  fourteen  miles  west  of  the 
Southern  Pacific  railroad  at  Corning.  iVo  investigation  was  made  of 
this  occurrence. 

O'Connor  Brotlicrs  liricki/ard.  Address,  Red  Blutf.  The  clay 
deposit  and  brickyard  are  on  the  Reed  Tract,  in  Sec.  29,  T.  27  X.,  R. 
8  \V.,  M.  D.  M.  The  deposit  covers  an  area  of  over  19  acres,  and  is 
from  8  to  12  feet  thick,,  underlain  by  gravel.  The  soft-mud  process  is 
used,  a  small  brick  ]iress  being  ojierated  by  horse  power.  The  brick 
are  fired  in  open  field  kilns.  The  plant  is  operated  intermittently  to 
supply  the  local  demand. 

Bibl :  State  Mineralogist 's  Rept.  XV,  p.  260 ;  State  Min.  Bur.  Bull. 
38,  pp.  258-259 ;  Prel.  Rept.  7,  p.  100. 


TULARE  COUNTY. 
General    Features. 

Tulare  County  is  in  the  southern  San  Joaquin  Valley,  and  is  bounded 
on  the  north  by  Fre.sno,  on  the  ea.st  by  Inyo,  on  the  south  by  Kern,  and 
on  the  west  by  Kings  County.  It  has  an  area  of  4856  square  miles,  and 
the  population  is  59,0.'U  (1920  census). 

The  western  half  of  the  county  lies  in  the  San  Joaf|uin  Valley,  and 
the  eastern  half  is  in  the  Sierra  Nevada,  culminating  in  a  number  of 
peaks  along  the  summit  at  elevations  exceeding  14,000  feet  above  sea 
level.  The  rocks  in  the  mountains  are  mainly  granites  and  other  ])lu- 
tonics,  whereas  the  valley  is  covered  with  Quaternary  sediments.  Vari- 
ous metamorphic  and  sedimentary  rocks  are  found  in  the  foothills. 

Climatic,  soil  and  water  conditions  in  the  foothills  and  in  the  San 
Joaquin  Valley  section  of  the  county  are  especially  favorable  to  the 
growth  of  citrus  fruits.  This  and  other  agricultural  pursuits,  includ- 
ing stock  raising  and  dairying,  are  the  principal  industries  of  the 
county. 

The  mineral  resources  of  the  county  include  brick,  clay,  copper,  feld- 
spar, graphite,  gems,  limestone,  magnesite,  marble,  quartz,  glas.s-sand, 
soapstone,  miscellaneous  stone,  and  zinc.  The  commercial  mineral 
products  are  brick,  granite,  lime,  limestone,  magnesite,  natural  gas, 
and  miscellaneous  stone,  of  which  magnesite  and  granite  are  the  most 
important. 

Clay   Resources. 

Common  clay  of  good  quality  for  the  manufacture  of  red-burned 
structural  ware  is  plentiful  in  the  valley  and  foothill  section  of  the 
county.     One  brickyard  has  been  in  operation  for  a  number  of  years. 

A  deposit  of  buft'-bui-ning  refractory  clay  has  been  found  eight  miles 
southeast  of  Ducor,  but  has  not  been  developed  commercially.  See 
under  Sears  Clay  Deposit. 

'Clay-Worker,  August,   1926,  p.  131. 


232  DIVISION  OF  MINES  AND  MINING 

Sears  Clay  Deposit.  W.  A.  Sears,  of  Porterville,  owner.  Eight 
miles  southeast  of  Diicor,  in  Sees.  26,  27,  35,  T.  24  S.,  R.  28  E.,  M.  D.  M. 
This  locality  was  visited  in  September,  1925,  but  the  author  was  unable 
to  meet  Mr.  Sears,  or  to  find  the  deposit  by  personal  search  or  by  inquiry 
among  residents  in  the  locality.  Later,  ^Ir.  Sears  sent  a  number  of 
samples  of  clav  from  the  property.  These  were  tested  under  numbers 
283-A,  283-B,  284,  and  285.  See  pages  314,  316,  and  282.  A  descrip- 
tion of  the  deposit  was  given  in  Preliminary  Report  No.  7,  p.  100,  and  is 
quoted  below : 

"The  clay  bearing  strata  extend  about  one-half  mile  south  of  White  River  and 
about  two  miles  in  length  along  the  south  bank  of  the  river.  An  overburden  of 
gravel  and  clay  6  to  8  feet  thick  overlies  a  bed  of  white  and  blue  plastic  clay.  A 
number  of  small  cuts  have  been  made  along  the  south  bank  of  the  river.  These  pits 
show  a  white  clay  6  to  8  feet  thick  overlying  a  blue  plastic  clay.  The  strata  of 
clay  beds  have  a  general  northwest  strike.  The  development  of  this  deposit  has 
been  only  superficial,  so  the  depth  of  the  clay  bed  has  not  been  determined.  The 
clay  is  suitable  for  tile,  sewer  pipe,  fire  brick,  vitrified  brick  and  terra  cotta." 

8.  P.  Brick  and  Tile  Co.  W.  D.  Trewhitt,  president ;  H.  W.  Shields, 
secretary-treasurer ;  H.  G.  Hayes,  superintendent.  General  office.  435 
Rowell  Building,  Fresno.  The  plant  is  three-quarters  of  a  mile  south 
of  Exeter,  in  Sec.  14,  T.  19  S.,  R.  26  E.,  M.  D.  M.  The  property  com- 
prises 20  acres,  all  of  which  is  underlain  by  workable  clay  to  a  depth 
of  12  to  18  ft.,  underlain  by  coarse  gravel.  The  products  of  the  plant 
are  common  brick  and  hollow  tile. 

The  clay  is  mined  by  a  i-yd.  electric  shovel,  having  a  capacity  of 
200  tons  per  eight  hours.  The  clay  is  passed  through  a  roll  disinte- 
grator, from  which  it  is  elevated,  screened,  and  passed  to  an  American 
pug-mill  and  auger  machine,  eciuipped  with  a  Freese  cutter.  Some 
of  the  ware  is  dried  under  sheds,  and  some  in  a  waste-heat  drier.  The 
drying  sheds  have  a  capacity  of  550,000  brick,  and  drying  is  usually 
completed  in  three  weeks.  The  waste-heat  drier  has  a  capacity  of 
135,000  brick,  and  the  drying  period  is  three  days. 

The  brick  and  tile  are  tired  in  open-field  kilns.  The  fuel  is  oil, 
atomized  with  steam.  The  firing  period  is  5i  days,  and  the  kiln  turn- 
over cycle  is  12  days.  Two  round  down-draft  kilns  are  available,  but 
are  not  used,  as  they  are  more  expensive  to  operate  than  the  field  kilns. 

The  capacity  of  the  plant  is  8,000,000  brick,  or  the  equivalent  volume 
of  brick  and  hollow  tile,  per  year. 

Valencia  Heights  Shale  Deposit.  C.  H.  Weed,  of  Porterville,  owner. 
The  deposit  is  six  miles  east  of  Porterville.  in  Sec.  34,  T.  21  S.,  R.  28  E., 
M.  D.  M.,  and  consists  of  black  clay  shale,  almost  a  slate.  The  shale 
is  1500  to  2000  feet  in  width,  and  cuts  through  a  serpentine  belt.  The 
strike  of  the  beds  is  northwest  and  the  dip  is  75°  SE.  Sample  No.  206 
was  taken  from  a  road  cut,  5.3  miles  from  Porterville.  The  test  results 
are  on  page  327. 

Bibl:  State  Min.  Bur.  Prel.  Rept.  7,  p.  101. 

Former  Operations. 

The  Pioneer  Brick  Company  and  the  ]\IcKnight  Firebrick  Company, 
mentioned  in  Preliminary  Report  No.  7,  pp.  100-101,  are  out  of  business. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  233 

VENTURA  COUNTY. 
General   Features.' 

Ventura  County  is  bounded  on  tlie  north  by  Kern  County,  on  tlie 
east  by  Los  Angeles  County,  on  the  south  by  Los  Angeles  County  and 
the  Pacific  Ocean,  and  on  the  west  by  Santa  Barbara  County.  The  total 
area  is  1878  square  miles.  The  population  as  shown  by  the  census  of 
1920  was  28,724. 

The  city  of  Ventura,  originally  called  San  Buenaventura,  is  the 
county  seat,  and  is  located  on  the  shores  of  the  Santa  Barbara  Channel. 
The  cities  of  Oxnard,  Santa  Paula,  and  Fillmore  are  next  in  importance. 

Ventura  County  is  essentially  an  agricultural  and  stock-raising 
county.  The  increasing  ])roduction  of  petroleum  in  the  i)a.st  few  years, 
however,  is  rapidly  bringing  it  forward  on  the  list  of  mineral-producing 
counties. 

The  northern  portion  of  the  county  is  characterized  by  the  converg- 
ence of  several  important  mountain  ranges,  which  make  of  it  a  high  and 
rugged  region.  The  moi'e  mountainous  and  rugged  parts  of  Pine  Moun- 
tain and  Topatopa  Mountain  form  what  is  considered  one  of  the  rough- 
est and  most  inaccessible  regions  in  California.  Its  lofty  peaks  range 
in  elevation  from  6000  to  9000  feet.  To  the  northwest  extend  the  San 
Emigdio  Mountains,  which  form  the  connection  between  the  Coast 
Range  and  the  Sierra  Nevada  Mountains.  To  the  west  extend  the  San 
Rafael  Mountains,  while  farther  southward  the  Santa  Ynez  Mountains 
diverge  from  this  group,  running  westward  through  Santa  Barbara 
County. 

The  southern  part  of  the  county  is  characterized  by  a  series  of 
]iarallel  folds,  the  axes  of  which  lie  east  and  west,  forming  low  moun- 
tain ranges  of  no  great  continuity.  The  principal  valleys  are  Santa 
Clara,  Ojai,  Simi,  and  Las  Posas. 

The  two  principal  drainage  systems  of  the  county  are  the  Santa 
Clara  River  and  the  Ventura  River.  Next  in  importance,  but  sub- 
ordinate to  these  is  Calleguas  Creek,  which  drains  the  Simi  and  Las 
Posas  valleys. 

The  county  is  traversed  by  the  Southern  Pacific  railroad,  with  a 
branch  line  from  Ventura  to  Ojai.  At  Montalvo,  five  miles  east  of 
Ventura,  the  main  line  divides  into  two  branches,  one  going  to  Los 
Angeles  via  Las  Posas  and  Simi  valleys,  the  other  through  the  Santa 
Clara  Valley,  joining  the  San  Joaquin  Valley  line  at  Saugus. 

With  the  exception  of  the  higher  mountainous  areas,  the  county  is 
easily  accessible  by  roads,  the  main  arteries  being  paved.  Access  to 
the  gold  and  borax  districts  is  obtained  over  the  state  highway  from 
Bakersfield  to  Los  Angeles  via  Tejon  Pass. 

Mineral    Resources. 

Ventura  was  the  fourth  county  in  the  state  in  respect  to  the  value  of 
its  mineral  production  in  1926.  Petroleum  and  natural  gas  are  the 
principal  products.  The  only  other  products,  in  1926,  were  miscel- 
laneous stone,  brick,  and  clay.  Undeveloped  resources  include  asphalt, 
borax,  diatomite,  gypsum,  limestone,  mineral  water,  mineral  paint, 
molding  sand,  phosphates,  and  sandstone. 

'  From  Tucker,  W.  Burling,  Ventura  County  :  State  Mineralogist's  Report.  XXI,  pp. 
223-225,  1925. 


234  DIVISION  OF  MINES  AND  MINING 

Geology. 

The  rocks  of  the  Ventura  rejiion  fall  into  three  classes :  a  meta- 
morphic  aud  granite  complex,  which  is  commonly  referred  to  as  the 
'basement'  complex,  a  series  of  sedimentary  rocks,  and  a  series  of 
igneous  extrusive  and  intrusive  rocks. 

The  metamor])hic  rocks  are  all  of  ])re-Jurassic  age  and  have  been 
intruded  by  granite  that  is  probably  of  the  same  age  as  that  of  the 
Sierra  Nevada,  which  is  considered  to  be  late  Jurassic  or  early 
Cretaceous. 

The  sedimentary  rocks,  which  in  this  region  form  the  greater  per- 
centage, range  in  age  from  Ui)i>er  Cretaceous  to  Recent. 

The  igneous  rocks  are  practically  all  of  Miocene  age  and  are  mainly 
andesite,  dacite,  basalt,  andesite  breccia,  and  associated  mud  flows. 

Clay   Resources- 
Common  clays  are  sufficiently  abundant  in  Ventura  County  to  serve 

all  purposes.     Two  brickyards  are  operated  as  needed  to  supply  the 

local  market. 

No  high-grade  clays  have  been  reported  in  the  county. 

Anderson  and  Hardison.  This  is  a  common  brick  ])lant,  2.7  miles 
north  of  Santa  Paula,  on  the  Ojai  Valley  road.  The  clay  is  obtained 
from  an  extensive  deposit  of  sandy  clay  and  is  mined  by  a  tractor- 
drawn  scraper.  The  clay  is  prepared  by  crushing  and  screening,  and 
the  brick  are  .shaped  by  dry  pressing.  So  far  as  known,  this  is  the 
only  brickyard  in  California  using  the  dry-press  process  of  making 
common  brick.     Gas-fired  field  kilns  are  used. 

Sample  No.  6  was  taken  for  testing.    The  results  are  on  page  389. 

Bibl:  State  Mineralogist's  Kept.  XXT,  p.  237. 

People's  Lumber  Company.  C.  E.  Bonistell,  general  manager.  Office 
in  Ventura.  Clay  pit  and  brickyard  on  the  Ventura  Avenue  road,  two 
miles  north  of  Ventura.  The  clay  is  mined  from  an  extensive  deposit 
of  Pliocene  (Fernando  ?)  age,  which  is  also  utilized  as  an  oil-well  mud. 
Two  varieties  of  clay  are  found :  a  yellow  clay,  .sample  No.  4,  p.  338, 
which  is  considered  best  for  use  in  making  brick,  and  a  bluish  clay, 
sample  No.  5,  p.  339,  which  is  more  fine-grained  and  plastic,  and  is 
especially  desirable  for  use  in  the  oil  fields.  Common  brick,  red 
ruffled  brick,  drain  tile,  roofing  tile,  and  hollow  building  tile  are  made, 
by  the  stiff-mud  ])rocess.  Open  field  kilns  are  used  for  firing,  and 
natural  gas  is  available  as  fuel. 

Bibl:  State  Mineralogist's  Repts.  XV,  p.  759,  and  XXI,  pp.  236- 
238.    Bull.  38,  p.  259 ;  Prel.  Rept.  7,  pp.  101-102. 


YOLO  COUNTY. 
General    Features. 

Yolo  County  is  in  the  Sacramento  Valley,  bounded  by  Sutter  on  the 
east  and  Colusa  on  the  north.  Its  area  i.s  1014  square  miles,  and  the 
population  is  17,105  (1920  census).  The  western  edge  of  the  county 
is  in  the  foothills  of  the  Coast  Range,  and  the  rest  of  the  county  is  in 
the  basin  of  the  Sacramento  River. 

The  only  commercial  mineral  resource  at  pre.sent  is  miscellaneous 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  235 

stone.     Quieksilver  was  at  one  time  produced.     Deposits  of  iron  and 
sandstone  have  been  noted. 

Clay   Resources. 

Common  hi-ick  clay  is  abundant  near  Winters,  Woodland,  and  Capay. 
Small  (juantities  of  brick  Avere  made,  chiefly  at  Woodland  and  Winters, 
ill  the  eighties,  usinji'  deposits  of  clay  and  clayey  k)ara. 

Bibl:  State  Mineralooist's  Kept.  X,  p.  791;  XIV,  p.  367.      State 
Min.  Bur.  Bull.  38,  p.  25!) ;  Brel.  Kept.  7,  p.  102. 

YUBA  COUNTY. 
General    Features. 

Yuba  County  lies  in  tlu^  north-central  part  of  the  state  and  borders 
the  east  side  of  the  Feather  Kiver.  It  is  bounded  on  the  northwest  by 
Butte  and  Plumas  counties,  on  the  southeast  by  Placer  and  Nevada 
counties,  and  on  the  east  by  Sierra  County.  Its  area  is  625  square 
miles,  and  the  i)opulation  is  10,375  (1920  census). 

Since  its  boundaries  extend  from  the  floor  of  the  central  valley  of 
California  to  the  middle  wester-n  slope  of  the  Sierra  Nevada  JMountains, 
Yuba  County  includes  diversified  topography  and  climate. 

Geology.' 

The  general  geology  of  Yuba  County  is  similar  to  that  in  Nevada  and 
Placer  counties.  The  main  central  portion  of  the  county  consists  gen- 
erally of  gabbro-diorite  and  granodiorite,  which  in  turn  grade  into 
metamoi-phic.  amphibolitic  rocks.  Schists  and  slates  in  ])laces  overlie 
the  igneous  rocks  and  arc  intruded  by  serpentine  in  the  northern  part 
of  the  county.  Alluvial  sands  and  gravels  cover  the  entire  western 
portion  of  the  county,  while  auriferous  gravels,  in  i)laces,  lie  along  the 
old  channel  courses. 

The  areal  geology  of  Yuba  County  has  been  covered  by  U.  S.  Geo- 
logical Survey  Folios  No.  17,  18  and"  43. 

Yuba  County  is  still  an  imj^ortant  producer  of  gold,  which  is  recov- 
ered by  dredging  and  hydraulic  mining.  Other  mineral  products  are 
miscellaneous  stone,  silver,  natural  gas,  and  i)latinum. 

Clay   Resources. 

High-grade  clay  in  small  quantities  has  been  mined  from  the  J.  F. 
Dem]isey  Kanch  (see  below)  near  Smartsville.  Common  clays  suitable 
for  tlie  manufacture  of  red-burned  structural  ware  are  plentiful  in  the 
vicinity  of  IMarysville. 

Dempsey  Ranch  Kaolin  Deposit.  A.  deposit  of  kaolin  fire  clay  occurs 
on  the  ranch  of  J.  F.  Dempsey,  in  the  E|  of  Sec.  3,  T.  15  N.,  R.  6  E., 
M.  D.  M.,  2  miles  southeast  from  Smartsville.  The  clay  occurs  as  irreg- 
ular bunches  exposed  in  small  chamber  workings  at  the  end  of  a  100- 
foot  tunnel.  The  clay  was  evidently  formed  by  the  alteration  in  place 
of  diabase  or  a  similar  intrusive  rock  which  penetrates  the  serpentine 
mass  of  the  hill  in  which  the  deposit  occurs.  The  clay  is  badly  con- 
taminated with  limonitic  iron  in  most  of  the  exposed  workings,  but 
occasional  bunches  of  5  to  10  tons  can  be  found  that  are  quite  free  from 

1  From  State  Mineralogist's  Rept.  XV,  p.  420. 


236  DIVISION  OF  MINES  AND  MINING 

iron.  It  is  doubtful  if  a  commercial  quantity  of  white  kaolin  could  be 
found. 

J.  V.  Chown  of  Oakland  at  one  time  held  a  lease  on  the  property, 
and  shipped  150  tons  of  kaolin  for  the  manufacture  of  fire  brick.  The 
kaolin  was  found  to  be  satisfactory'  for  this  purpose,  but  on  account  of 
the  isolation  of  the  property,  expensive  mining,  and  the  irregular 
occurrence  of  the  clay,  it  was  not  possible  to  compete  with  other  sources 
of  material.  The  kaolin  was  hauled  20  miles  to  Marysville,  over  a 
rough  road,  at  a  cost  of  $5  per  ton  for  haulage  alone. 

8ami)le  No.  173  was  taken  for  testing.     The  results  are  on  i)age  313. 

Durst  Ranch.  One-half  mile  east  of  Wheatland.  This  locality  was 
not  visited,  but  a  note  on  the  occurrence  of  clay  on  this  property  was 
given  in  earlier  reports  as  follows:  "Shipments  of  clay  were  occa- 
sionally made,  before  1905  ...  to  Gladding,  McBean  and  Company 
at  Lincoln.  .  .  .  The  black  clay  loam  used  was  6  feet  deep  and  over- 
lain by  18  inches  of  soil.  Deposits  similar  to  that  on  the  Durst  Ranch 
are  abundant  in  the  valley  portion  of  Yuba  County."^ 

Marysville  Brick  Company.  This  plant  is  a  short  distance  north  of 
Marysville,  on  the  Feather  River.  A  local  surface  clay  is  used  for  the 
manufacture  of  common  brick.  The  plant  was  not  visited  and  no 
details  are  available  for  publication.  The  production  in  1925  was 
1,100,000  brick.2 

1  state  MineraloRist's  Rept.  XV,  p.  424,  1915-16,  evidently  abstracted  from  Bull. 
38,   p.   230,    1906. 

=  Clay-Worker,    February,    1926,   p.    139. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  237 


Chapter  IV. 

CLAY  TESTS  AND  THEIR  INTERPRETATION  AND  THE 
CLASSIFICATION  OF  CLAYS. 

FIELD  TESTS. 

While  uo  field  tests  of  clays  were  made  in  preparing  this  report,  tiie 
prospector  or  clay  miner  often  wishes  to  deternune  the  possible  eco- 
nomic value  of  clays  before  incurring  the  labor  or  expense  of  securing 
adequate  samples  and  sending  them  to  clay  ])]ants  oi'  commercial  labora- 
tories for  testing.  If  samjjles  are  sent  to  clay  plants  it  is  usually  neces- 
sary to  send  material  to  more  than  one  plant,  as  a  clay  may  be  rejected 
by  one  operator  as  not  being  suitable  for  his  ware  or  his  plant  routine, 
but  this  same  clay  may  be  eminenth'  suitable  in  some  other  plant. 

The  following  sim[)le  field  tests  for  making  a  rough  preliminary 
classification  of  clays,  from  the  Third  Report  of  the  West  Virginia 
Geological  Survey,  have  been  quoted  many  times,  but  are  of  such  gen- 
eral interest  to  ])rospectors  and  others  who  are  searching  for  clays  in 
the  field,  that  they  are  repeated  here. 

1.  A  small  lump  of  clay  may  be  roasted  in  the  flame  of  a  gas  stove. 
If  it  turns  red  or  brown,  the  percentage  of  iron  is  high,  probably  more 
than  four  per  cent. 

2.  By  tasting  the  clay,  bitter  salts,  such  as  alum  and  epsom,  may  be 
detected,  or  such  salts  may  occur  a&  white  coatings  on  the  outcrops 
of  the  clay  in  the  bank.  These  salts  are  apt  to  form  white  wash  coats 
on  the  finished  brick,  injuring  their  appearance.  Sand  may  be  detected 
by  grit  against  the  teeth.  A  rough  idea  of  the  percentage  of  such  sand 
may  thus  be  made. 

3.  A  good  idea  of  its  plastic  qualities  may  be  obtained  by  working 
the  moist  clay  with  the  fingers.  A  good  test  for  pottery  clay  is  to 
thus  moisten  it,  and  determine  whether  it  can  be  worked  into  a  definite 
shape,  and  whether  or  not  it  will  retain  its  form  when  dry  without 
cracking. 

4.  Shrinkage :  A  rough  brick  can  easily  be  made  and  dried,  and  a 
good  idea  of  the  shrinkage  arrived  at.  If  it  cracks  or  crumbles  when 
dry  or  shrinks  out  of  shape,  its  value  is  very  doubtful.  For  this  test, 
however,  the  clay  should  be  ground  thoroughly,  tempered  with  water, 
and  dried  slowly. 

5.  If  carbonates  of  lime  are  present,  a  few  drops  of  hydrochloric 
acid  will  cause  effervescence  or  bubbling,  as  the  carbonic  acid  gas 
passes  off.  Very  high  percentages  of  lime  are  apt  to  ruin  the  clay. 
Good  fire  bricks  are  made  of  clay  low  in  lime  content. 

6.  The  slaking  of  clays,  or  the  crumbling  down  in  tempering  is  tested 
by  dropping  a  lump  of  clay  in  a  cup  of  water.  Some  clays  slake  in  a 
very  few  minutes,  and  so  are  easily  tempered. 

7.  The  color  of  a  finished  clay  product  is  largely  determined  by  the 
amount  of  iron  present.  It  is  not  always  possible  to  predict  the  color 
of  the  burned  ware  from  the  color  of  the  clay.  It  is  true  that  red  clays 
will  usually  burn  red,  but  blue  clays  or  those  of  other  shades  also  com- 
monly burn  red  or  buff.  The  color  of  the  raw  clay  is  often  due  to 
organic  matter  which  is  combustible,  and  will  be  consumed  in  the 
burninor. 


238  DIVISION  OF  MINES  AND  MINING 

While  the  above  tests  may  not  prove  absolutely  the  quality  of  any 
fjiven  elay,  at  the  same  time  they  furnish  considerable  valuable  infor- 
mation in  i-e^rard  to  it,  and  may  be  used  to  advantage  by  the  owner  of 
a  deposit  which  has  never  been  developed.  If  these  simple  tests  seem 
to  give  ))ositive  results  it  may  then  be  well  worth  while  to  get  in  touch 
with  buyers  and  consumers. 

LABORATORY  TESTS. 

The  methods  of  testing  used  for  this  report  followed  the  standards 
or  tentative  standards  of  the  American  Ceramic  Society,^  in  so  far 
as  it  was  i)Ossible  to  do  so  with  the  ecpiipment  and  funds  available. 

These  methods  or  their  equivalent  have  been  followed  in  a  number 
of  recent  state  reports  on  clays.-  Only  such  explanation  of  the  testing 
methods  and  their  inter])retation  is  given  here  as  is  necessary  to  an 
understanding  of  the  text  of  this  rei)ort  and  to  indicate  the  divergences 
from  the  recommended  methods.  The  reader  is  referred  to  the  litera- 
ture for  further  details. 

Preparation  of  Samples. 

The  weight  of  the  sample  collected  in  the  field  was  usually  a]i]iroxi- 
mately  fifty  pounds,  but  a  number  of  them  were  smaller,  owing  to 
s]:)ecial  difficulties  of  secnring  proper  samples  or  of  transporting  them. 
In  sampling,  the  usual  precautions  were  taken  to  secure  material  that 
was  representative  of  the  clay  tluit  would  actually  be  mined.  Notes  on 
the  macroscoi)ic  character  of  the  material  sampled  were  made  at  the 
time  of  sampling,  and  are  recorded  in  the  description  of  the  sam]ile.  if 
of  special  interest.  All  foreign  matter  that  normally  would  not  be 
mixed  with  the  elay,  or  that  would  be  removed  by  screening  before  the 
clay  is  used  in  a  elay-AAorking  plant,  was  removed  from  the  sample 
before  shipment  to  the  laboratory. 

In  the  laboratory,  the  entire  sample  was  crushed  to  pass  a  20-mesh 
screen,  by  passing  through  a  laboratory  jaw-crusher,  followed  by  pass- 
ing through  a  set  of  rolls.  One  samjile,  a  flint  fireclay  (samjile  Xo. 
282),  was  further  crushed  in  a  pebble  mill  to  develo})  maximum 
plasticity. 

Sufficient  water  was  added  to  the  ground  clay  to  permit  the  mixture 
to  be  Avorked  into  a  plastic  condition.  The  attemi)t  was  made  to  main- 
tain a  uniform  consistency,  so  that  all  determinations  of  water  of 
plasticity  and  drying  shrinkage  would  be  comparable,  but  with  a  series 
of  clays  of  widely-varying  plastic  properties,  it  is  impossible  to  attain 
a  high  degree  of  uniformity  in  the  ])lastic  state,  without  the  use  of 
more  elaborate  methods  than  the  scope  of  the  investigation  warranted. 

After  thoroughly  working  (wedging)  the  plastic  mass,  it  was  covered 

•  Report  of  the  Committee  on  Standards.  American  Ceramic  Society,  Reprint  from 
Yearbook,   1921-22,   Ohio   State  fniversity,   Columbus,   Ohio.      Price   fifty  cents. 

-  Wilson,  Hewitt,  The  Clays  and  Shales  of  Washington,  Their  Technology  and  Uses, 
Bull.  No.  18.  University  of  "Washington,  Engineering  Experiment  Station,  Seattle, 
Washington,  October,  1923. 

Skeels,  F.  H.,  and  Wilson.  Hewitt,  Preliminary  Report  on  the  Clays  of  Idaho.  Bull. 
No.  2,  Department  of  Mines  and  Geology,  Idaho,   1920. 

Parmelee,  C.  W.,  and  Schroyer,  C.  R.  Further  Investigations  of  Illinois  Fire  Clays, 
Bull.  No.  38,  pp.  273-417.      Illinois  Geological  Survey,  1922. 

Reis,  H.,  The  Clays  of  Kentucky,  Ky.  Geol.  Surv.  Series  VI.  Vol.  8,  Frankfort,  Ky., 
1921. 


CLAY  RESOURCES  AND  CERA^FTC  TXDT'STRY  239 

with  wot  sacking  and  seasoned  foi-  at  least  24  hoiii-s  before  test  pieces 
were  i)repared. 

Test  Pieces. 

The  test  pieces  were  shaped  in  l)rass  molds,  1}  in.  by  1 J  in.  by  8  in., 
inside  dimensions.  Full  lenoth  bars  were  nsed  for  dry  transverse- 
strength  tests,  and  test  i)ieees  for  drying  and  firing  data  were  made  by 
cutting  the  bars  into  four  pieces.  A  minimum  of  four  8-in.  bars  and 
sixteen  2-in.  test  pieces  were  made  for  all  important  clays  of  which 
there  was  a  sufficiently  large  sample.  The  i)lastic  weight  and  volume 
of  three  test  i)ieces  were  determined  as  soon  as  they  were  molded.  All 
volume  measurements  were  made  in  a  Goodner  mercury  volumeter.^ 

Drying. 

The  test  pieces  and  bars  Avere  thoroughly  air  dried  in  the  laboratory, 
then  heated  in  an  automatic  electric  oven  for  five  hours  at  a  tem])erature 
between  64=  C.  and  7G  C.  and  finally  at  105  to  110°  C.  for  at  least 
12  hours.  They  were  then  transferred  to  a  desiccator,  where  they 
remained  until  needed  for  dry  weight  and  volume  measurements,  and 
for  the  dry  transvei-se-strength  test. 

Plastic  and  Drying  Properties. 

Phisticihj  :  Notes  on  i)lasticity  and  molding  properties  were  made  at 
the  time  the  test  bars  were  molded.  There  is  no  satisfactory  standard 
test  or  even  a  standard  nomenclature  to  describe  the  plasticity  of  a 
clay  in  unambiguous  terms.  The  term  'good  ])lasticity'  means  a  differ- 
ent condition  to  the  common  brick  worker  than  it  does  to  a  stoneware 
worker.  In  general,  the  plasticity  terms  used  in  this  report  bear  some 
i-elation  to  the  ty]iical  uses  of  the  clay  in  question.  The  words  'short,' 
'weak,'  'crumbly,'  'smooth,'  and  'sticky'  are  used  wherever  they  serve 
to  clarify  the  meaning  of  tiie  more  general  words  'poor,'  'fair,'  'good,' 
and  'excellent.' 

Some  shales  and  indurated  clays  can  be  rendered  more  ])lastic  by 
fine  grinding.-  The  test  data  on  such  clays  are  of  little  value  without 
l)articular  reference  to  the  preliminary  preparation  of  the  sample. 

Water  of  Phisficifii:  The  water  of  i)lasticity  is  tlie  amount  of  water 
required  to  render  a  clay  readily  workable.  It  is  calculated  as  a  per- 
centage of  the  Aveight  of  the  dry  clay  bar,  according  to  the  following 
formula  : 

plastic  wcifjht — dry  weight 

Per  cent  water  of  plasticity  = X  100  (1  I 

dry  weisiit 

Shrinkage  Waier:  The  water  that  is  removed  from  a  clay  while  it  is 
shrinking  from  the  pla.stic  to  the  dry  state  is  called  the  shrinkage  water. 
It  is  calculated  as  follows: 

Plastic  volume — dry  volume 

Per  cent  shrinkage  water  = X  100  (2) 

dry  weight 


'  Goodner,  E.  F.,  A  Mercury  Volumeter,  Jour.  Am.  Cer.   Soc.  Vol.   4,  p.  228,  1921. 
-  Walker.  T.  C.  The  Effect  of  Fine  Grinding  on  an  Industrial  Clay.     Jour.  Am.  Cer. 
Soc,  Vol.  10,  p.  449,  June.  1927.      (A  Southern  California  clay  was  used  in  this  study.) 
See  also  the  results  on  sample  No.  2S2,  this  report,  page  2S2. 


240  DIVT^'O"'  •"     Ay  "MINING 

Pore  Wafer:  Pore  "vvater  is  that  jiortion  of  tlie  water  of  plasticity 
that  is  retained  in  the  pores  after  shrinkage  ceases.  It  is  calculated  as 
follows : 

Per  fiMit  iM)i('  w.iter  ^  per  cent  water  ol'  plasticity  —  per  cent  shriukage  water      (8) 

Clays  in  which  the  percentage  of  shrinkage  water  is  high  may  have 
excessive  or  sticky  plasticity,  and  usually  must  be  carefully  dried  to 
prevent  warping  or  cracking.  According  to  A.  V.  Bleininger/  the 
ratio  of  pore  to  shrinkage  water  shoidd  not  exceed  1.00  for  bond  clays, 
nor  0.75  for  strong  heavy  plastic  clays. 

Shrinkage :  Drying  shrinkage  is  most  accurately  determined  by 
determining  the  volume  shrinkage,  then  calculating  the  linear  from  the 
volume  shrinkage.  Volume  shrinkage  is  calculated  as  follows,  in  per- 
centage of  dry  volume. 

plastic  volume — dry  volume 

Per  cent  dry  volume  shrinkage  = X  100  (4) 

dry  volume 

The  linear  drying  shrinkage,  in  per  cent  of  drj^  length,  is  calculated 
as  follows: 

Calculated  linear  diying  shrinkage  = 


[,3/            drv  volume  shriukage  f 

V  1  + .     —  1  X  lOU  (5) 

100  J 

In  addition  to  calculated  values  of  linear  drying  shrinkage,  direct 
measurements  were  made  by  means  of  shrinkage  marks  on  the  8-in. 
bars.  These  measurements  are  not  reported,  as  they  are  inaccurate, 
and  serve  only  as  an  approximate  check  on  the  calculated  values. 

For  many  purposes,  the  drying  shrinkage  is  expressed  in  per  cent 
plastic  volume  or  length.  Either  of  these  may  be  calculated  from  the 
data  given  in  this  rei)ort  by  means  of  the  following  formulas: 


Volume  drying  shrinkage,  per  cent  plastic  volume  = 

volume  drying  shrinkage,  per  cent  dry  volume 

100  +  volume  drying  shrinkage,  per  cent  dry  volume 

Linear  drying  shrinkage,  per  cent  plastic  length  = 

linear  drying  shrinkage,  per  cent  dry  length 

100  +  linear  di\ving  shrinkage,  per  cent  dry  length 
Linear  drying  shrinkage,  per  cent  plastic  length  = 


X  100  (G) 


X  100  (7) 


-  f/i 


vol.  dry.  shrink.,  %  plastic  vol. 
100 


X  100  (8) 


For  convenience  in  making  the  large  number  of  calculations  for  this 
report,  tables  of  values  were  prepared  for  equations  (5)  and  (8).  As 
■will  be  noted  later,  equation  (8)  is  the  proper  form  to  use  for  the 
calculation  of  linear  firing  shrinkage,  in  per  cent  of  dry  volume. 

Dry  Transverse  Strength :  The  dry  modulus  of  rupture  was  deter- 
mined on  practically  all  of  the  clays  tested.     The  8-in.  dried  test  bars 

'  Bleininger,  A.  V.,  Properties  of  American  Bond  Clays,  etc.,  U.  S.  Bur.  of  Stand- 
ards, Tec.    Paper  No.    144,  p.   51,   1920. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  241 

"were  of  such  a  lenjjtli  that  one  jl-in.  Iji-cak  and  two  ■^-'n\.  breaks  could 
be  obtained  on  each  bar.  Tlie  bars  rested  on  ^-in.  rollers,  and  the  pull 
stirruj)  also  was  efiuipped  with  a  roller-bearing^  surface,  so  that  the 
daufier  of  shear  breaks  was  niinimized.  Xo  difference  was  noted  in  the 
average  values  obtained  on  the  o-in.  and  the  8-in.  breaks.  At  least  ten 
breaks  were  made  on  all  clays  of  which  sufficient  material  was  available 
for  making  the  requisite  number  of  test  bars.  A  variation  of  plus  or 
minus  15%  from  the  average  modulus  of  rupture  was  allowed,  and 
at  lea.st  eight  out  of  ten  breaks  came  within  these  limits,  unless  noted 
in  the  text  by  tlie  approxinuition  symbol  (zh).  Where  necessary,  the 
tests  were  repeated  until  a  set  of  consistent  i-esults  was  obtained. 
The  modulus  of  rupture  is  calculated  by  the  following  formula : 

Modulu.s  of  rupture,  lb.  per  sq.  in  = 

3   X   breaking  load  in  pounds   X   distance  between  supports  in  inches 

(9) 

2  X  breadth  in  inches  X    (deptii  in  inches )-' 

On  the  stroiiger  clays,  especially  on  the  3-in.  breaks,  it  was  necessary 
to  use  a  lever  Avith  a  ratio  of  2.86.  The  lever  ratio  is  multiplied  by  the 
breaking  load  to  determine  the  breaking  load  at  the  point  of  application 
for  use  in  equation  (9). 

A  nomogra{)]i  was  used  to  minimize  tlie  calculations  involved. 

The  following  classification  of  clays  by  modulus  of  rupture  is  used  in 
the  text  of  this  report : 

Metlium  Medium 

Low  low  Medium  hiffh  High 

Modulus,  lb.  per  sq.  in 0  to  100     100  to  200     200  to  400     400  to  SOO     above  800 

This  is  the  same  classification  as  that  suggested  by  "Watts  ^  for  bond- 
ing strength  (q.  v.  below)  and  is  an  elaboration  of  that  used  by  Parme- 
lee  and  Schroyer.- 

Bonding  Strength:  The  modulus  of  rupture  of  dried  bars  containing 
equal  parts  of  clay  and  standard  Ottawa  sand  ■'  is  known  as  the  bonding 
strength.  It  is  of  importance  in  all  clays  that  are  to  be  used  with  non- 
l)lastic  material.  A  few  bonding  strength  determinations  w^ere  made 
for  this  report.  See  samples  No.  83,  273  and  280,  pages  297,  273  and 
305.  It  was  intended  to  include  more  of  tliese  determinations,  but  it 
was  found  that  to  do  so  would  unnecessarily  delay  the  publication  of 
this  report.  For  an  especially  interesting  comparison  between  dry 
modulus  of  rupture  and  'bonding  strength,'  the  reader  is  referred  to 
the  test  results  of  Parmelee  and  Schroyer.*  It  will  be  noted  that  in 
some  cases  the  bonding  strength  is  higher  than  the  dry  modulus,  but 
that  in  general  the  addition  of  50%  of  sand  to  a  clay  lowers  the  trans- 
verse strength  by  30%  to  60%)  of  its  original  value. 

Fineness:  The  percentage  of  non-plastic  material  remaining  on  a 
200-mesh  (0.0029  in.  ajierture)  screen  was  determined  for  most  of  the 
clays  tested.  Fifty  grams  of  the  clay  was  taken,  broken  in  a  mortar 
and  passed  through  a  10-mesh  screen.     The  sample  was  placed  in  an 

1  Watts,  A.  S.,  Classification  of  Clays  on  a  Ceramic  Basis.  Jour.  Am.  Cer.  Soc, 
Vol.  3,  p.  247,  1920. 

2  Parmelee,  C.  W.,  and  Schroyer,  C.  R.,  op  cit..  p.  293. 

^Standard  sand  is  sized  between  the  limits  of  minus  20-mesh   (0.0328  in.  aperture) 
'•nd  plus  2S-mesh   (0.02."i2  in.  aperture).     It  i.s  used  in  the  testing  of  cement. 
*  Op.  cit. 

16 — 54979 


242 


DIVISION  OP  MINES  AND  MINING 


Erlenmever  flask  -with  150  ce.  of  distilled  -water  and  1  cc.  of  ammonia. 
The  i)ul])  was  thoi-ouglily  shaken,  let  stand  for  18  liours,  and  agitated 
for  10  minutes  in  a  shalving  machine  such  as  that  commonly  used  in  the 
phosphorus  determination  in  steel.  The  pulp  was  transferred  to  a 
200-mesli  screen,  and  all  nndersize  was  -vvashod  through  the  screen  with 
a  fine  jet.  The  oversize  was  dried  and  weighed,  and  the  result  reported 
in  per  cent  of  plus  200-mesh  material. 

Firing  Properties. 

Firing  Treatment :  A  test  piece  of  each  clay  was  fired  to  each  alter- 
nate cone  number  from  cone  010  to  cone  13,  except  where  insufficient 


Photo  No.  G7. 


Assay  laboratory,   Stanford   University,   showing  nuitfle  furnaces 
in  which  test  pieces  were  lired. 


material  was  available  to  make  enough  test  pieces  for  the  complete 
series.  In  addition,  most  of  the  refractory  clays  were  fired  to  cone  15. 
Denver  Fire  Cla.y  Company  oil-fired  assay  muffle  furnaces  were  used 
for  all  firing  from  cone  010  to  cone  13.  These  furnaces,  shown  on 
photo  No.  67,  were  very  satisfactory  for  the  purpose,  as  the  tempera- 
tures could  be  readily  controlled,  and  since  ten  furnaces  w^ere  available, 
it  was  possible  to  place  one  or  two  sets  of  30  samples  in  each  muffle. 
If  two  sets  of  test  pieces  were  placed  in  the  same  muffle,  the  set  in  the 
rear  of  the  muffle  was  fired  to  two  cones  higher  temperature  than  the 
set  in  the  front,  and  the  two  sets  were  separated  from  each  other  by  a 
full  sized  fire  brick.  This  method  of  firing  eliminated  most  of  the  trans- 
ferring of  test  pieces  to  a  cooling  furnace  that  is  a  disagreeable  and 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


243 


unsatisfactory  feature  of  most  test  Avork  of  this  kind.  The  bottom 
tiers  of  test  pieces  were  kept  from  contact  with  the  muffle  floor  by 
placinj;  tliom  on  .small  fircchiv'  saddh^s.  Tlie  fiiniaec  tliat  was  used  for 
firing  to  cones  11  and  1:5  was  ('(juipped  with  a  Carbofrax  muffle,  and 
with  Carbofrax  stools  and  muffle  i)rotector  plates.  It  was  difficult  to 
fire  to  these  temperatures  without  flashing  the  test  pieces. 

A  Fisk  ^  pre-mix  ga.s-fired  kiln  was  u.sed  for  firing  to  cone  15.     This 
furnace,  shoAvn  on  photo  No.  68,  has  a  12-in.  circular  firing  chamber, 


Photo  No.  68.  Fisk  pre-mix  gas-fired  labora- 
tory kiln,  in  ceramic  laboratory,  Stanford 
University.  This  is  used  as  a  load  and 
spall  furnace  and  for  firing  tests  to  a 
maximum  temperature  of  cone  30  (1650° 
C).  All  cone  15  tests  were  fired  in  this 
kiln. 

and  is  capable  of  accurate  temperature  control  and  good  heat  distribu- 
tion. The  same  furnace  is  used  for  load  and  spall  tests  of  refractories, 
and  is  suitable  for  test  work  up  to  cone  30  (1650°  C). 

Pyrometric  Control:  Temperatures  were  controlled  with  the  aid  of 
base-metal  or  preciou.s-metal  thermocouples,  in  addition  to  Orton  stand- 
ard pyrometric  cones  alongside  the  test  pieces.     The  firing  schedule 

'  Fisk,  H.  G.,  A  Practical  Gas-Fired  Test  Furnace  for  Plant  Use.  Jour.  Am.  Cer. 
Soc,  Vol.  9,  p.  151,  March,  1926. 


244 


DIVISION  OF  MINES  AND  MINING 


was  at  a  rate  50 '^f  faster  than  the  fastest  schedule  recommended  by 
the  American  CVramic  Society,  aA'era<rinfr  ajiproximately  90°  C  per 
hour,  but  at  a  shiwer  rate  during  the  Avater-smoking  period,  a  faster 
rate  between  the  ranp:e  of  600°  C.  and  100°  C.  below  the  desired  finish- 
ing temperature,  and  a  slower  rate  again  at  the  finish.  While  this 
schedule  caused  more  shattering  and  splitting  of  some  of  the  test  pieces 
than  would  have  been  the  case  if  a  slower  schedule  had  been  followed, 
the  data  on  shrinkage  and  porosity  at  various  firing  temperatures  are 
comparable  with  each  other,  and  can  be  correlated  with  the  results  that 
liave  Ix'cn  reported  by  other  investigators/  Tn  the  final  analysis,  no 
laboratory  tests  of  clays  can  be  interpreted  in  a  strict  quantitative 
sense  with  the  results  obtained  in  commercial  practice,  and  the  purjiose 
of  the  small-scale  tests  is  to  tentatively  classify  a  given  clay  according 
to  its  commercial  uses  with  the  minimum  expenditure  of  time  and 
money.  The  final  decision  as  to  tlie  utility  of  a  clay  and  the  methods 
of  working  it  to  obtain  the  best  results,  must  always  be  determined  in 
a  commercial  plant,  where  the  shaping,  drying  and  firing  can  be  done 
on  full-sized  ware. 

For  convenience  of  reference,  the   end  points  of   Orton   cones  are 
given  in  degrees  Centigrade  and  Fahrenheit,  in  table  No.  9. 


TABLE    No.  9. 
End   Points  of  Orton   Pyrometric  Cones,  in  Centigrade  and   Fahrenheit   Degrees 

(Heated   in  Air). 

(From   Fail-child,   C.   O.,   and   Peters,   M.   F.,   Characteristics  of   Pyrometric   Cones, 
Jour.  Amer.  Cer.  Soc,  Vol.  9,  p.  738,  1926.) 


• 

End  point 

End  point 

Heated 

Heated 

Heated 

Heated 

Cone 

at  20 

'  C./hr. 

at  150° 

C./hr. 

Cone 

at  20" 

C./hr. 

at  150° 

C./hr. 

No. 

".C. 

"F. 

°  C. 

°F. 

No. 

"C. 

"F. 

°  C. 

°  F. 

022 

585 

1085 

605 

1121 

11 

1285 

2345 

1325 

2417 

021 

595 

1103 

615 

1139 

12 

1310 

2390 

1335 

2435 

020 

625 

1157 

650 

1202 

13 

1350 

2462 

1350 

2462 

019 

630 

1166 

660 

1220 

14 

1390 

2534 

1400 

2552 

018 

670 

1238 

720 

1328 

15 

1410 

2570 

1435 

2615 

017 

720 

1328 

770 

1418 

16 

1450 

2642 

1465 

2669 

016 

735 

1355 

795 

1463 

17 

1465 

2669 

1475 

2687 

015 

770 

1418 

805 

1481 

18 

1485 

2705 

1490 

2714 

014 

795 

1463 

830 

1526 

19 

1515 

2759 

1520 

2768 

013 

825 

1517 

860 

1580 

20 

1520 

2768 

1530 

2786 

012 

840 

1544 

875 

1607 

Oil 

875. 

1607 

905 

1661 

23 

In  Arsem 

1580 

2876 

26 

furnace  at 

1595 

2903 

010 

890 

1634 

895 

1643 

27 

600»C.(: 

=  1080°F.) 

1605 

2921 

09 

930 

1706 

930 

1706 

28 

per  hr 

. 

1615 

2939 

08 

945 

1733 

950 

1742 

29 

1640 

2984 

07 

975 

1787 

990 

1814 

30 

1650 

3002 

06 

1005 

1841 

1015 

1859 

05 

1030 

1886 

1040 

1904 

31 

1680 

3056 

04 

1050 

1922 

1060 

1940 

32 

1700 

3092 

03 

1080 

1976 

1115 

2039 

33 

1745 

3173 

02 

1095 

2003 

1125 

2057 

34 

1755 

3191 

1760 

3200 

01 

1110 

2030 

1145 

2093 

35 

1775 

3227 

17  85 

3245 

36 

1810 

3290 

1810 

3290 

1 

1125 

2057 

1160 

2120 

37 

1830 

3326 

1820 

3308 

2 

1135 

2075 

1165 

2129 

38 

1850 

3362 

1835 

3335 

3 

1145 

2093 

1170 

2138 

39 

1865 

3389 

4 

1165 

2129 

1190 

2174 

40 

1885 

3425 

5 

1180 

2156 

1205 

2201 

6 

1190 

2174 

1230 

2246 

41 

1970 

3578 

7 

1210 

2210 

1250 

2282 

42 

2015 

3659 

8 

1225 

2237 

1260 

2300 

9' 

1250 

2282 

1285 

2245 

10 

1260 

2300 

1305 

2381 

'  See  In  this  connection  :  Brown,  G.  H.,  and  Murray,  O.  A.,  The  Function  of  Time 
in  the  Vitrification  of  Clays,  Trans.  Am.  Cer.  Soc,  Vol.  XV,  p.  193,  1913. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  245 

Firing  Shrinkage:  The  shrinkage  resulting  from  firing  may  be 
expressed  as  the  per  cent  volume  or  linear  shrinkage,  in  terms  of  plastic 
or  tlry  volume  or  lengtli.  The  data  in  this  report  are  given  in  terms  of 
volume  and  linear  shrinkage,  dry  basis,  and  in  the  written  summaries  of 
each  clay,  the  maximum  total  linear  shrinkage,  plastic  basis,  is  given. 
The  equations  for  calculating  these  various  methods  of  expressing  fired 
shrinkage  from  the  volume  determinations  are  as  follows: 


^'ohime  firiiif;  sliriiikage.  per  ot'iit  dry  volume  = 

dry  volume — fired  volume 


dry   volume 
Linear  firing  shrinkage,  per  cent  dry  length  = 


X  100  (10) 


yV  volume  firing  shrinkage.  %  dry  volume 


I               vV              volume  nring  snrinKage.  Vr  (iry  volume 
1   —     V  1 X  too  (11) 

L  100  J 

(See  equation  S) 

Total  linear  shrinUagt'.  per  cent  plastic  length  = 
(lin.  dry  shrink.,  %  dry  length  +  lin.  firing  shrink.  %  dry  length) 


100  +  lin.  dry  shrink.,  '/c  dry  length 


X  100  (12) 


All  fired  volume  measurements  were  made  in  the  mercury  volumeter 
after  saturating  the  test  pieces  with  water^  and  weighing  them  for  the 
absorption  and  apparent  porosity  calculations.  In  this  way,  the  volume 
measurements  ap])roximate  the  bulk,  or  outside,  volume  of  the  test 
pieces,  as  the  mercury  does  not  readily  enter  the  small  pores  and  dis- 
place water,  during  the  short  time  of  contact  in  the  volumeter.  How- 
ever, some  mercury  undoubtedly  enters  the  larger  of  the  open  pores 
(excluding  from  consideration  all  vugs,  cavities  and  drying  or  firing 
cracks),  hence  the  calculations  of  volume  and  linear  firing  shrinkage, 
as  well  as  those  of  absorption,  apparent  porosity,  apparent  specific 
gravity,  and  apparent  density,  are  slightly  erroneous. 

Absorption:  The  absorption  of  fired  test  pieces  was  determined 
by  noting  the  weight  of  water  absorbed  by  boiling  the  piece  in  distilled 
water  for  two  hours. 


I'er  cent  absorption  = 


saturated  weight — dry  fired  weight"! 


X  100  (13) 


dry  firwl  weight  J 

Apparent  Porosity:  Apparent  porosity  is  the  ratio  between  the  volume 
of  the  unsealed  pores  and  the  volume  of  the  whole  piece  (=bulk  vol- 
ume).   It  is  calculated  from  the  following  equation: 

saturated  weight — dry  fired  weightl 

1   X  100      (14) 


Per  cent  apparent  porosity 


fired    volume 


Apparent  Specific  Gravity:  Apparent  specific  gravity  or  bulk 
specific  gravity  is  the  relation  between  the  weight  of  a  mass  of 
material  as  a  whole  and  that  of  a  volume  of  water  equal  to  the  volume 
of  the  solid  material  plus  the  sealed  i)ores^.     No  values  of  apparent 

'  The  pieces  were  boiled  in  distilled  water  for  at  least  two  hours,  tlien  allowed  to 
cool  in  tlie  water.  Before  weighing,  the  surplus  water  was  removed  from  the  surface 
of  the  test  pieces  witli  a  damp  cloth. 

-  Searle,  A.  B.,  The  Chemistrv  and  Phvsics  of  Clays  and  other  Ceramic  Materials, 
p.  203. 


246  DIVISION  OF  MINES  AND  MINING 

specific  gravity  are  given  in  this  report,  but  they  may  be  calculated 
for  the  fired  test  pieces  from  the  absorption  and  apparent  density,  if 
these  are  not  zero,  according  to  the  following  equation : 

Apparent  specific  gravity  = 

per  cent  apparent  porosity  X  100 

(15) 

percent  absorption  X   (100 — percent  app.  porosity) 

Apparent  Density:  Apparent  density  or  bulk  density  is  the  relation 
between  the  weight  and  volume  of  an  article  or  material  as  a  w^hole 
(including  any  pores  or  voids)  and  that  of  the  weight  of  an  equal 
volume  of  waters  Values  of  apparent  density  are  not  given  in  this 
report,  but  if  the  absorption  and  apparent  porosity  are  not  zero,  the 
apparent  density  can  be  calculated  as  follows: 

per  c-ent  apparent  porosity 

Apparent  density  = (16) 

per  cent  absorption 

True  Specific  Gravity:  True  specific  gravity  is  the  relation  between 
the  Aveight  of  a  substance  and  the  true  volume  of  the  grains  of  wdiich 
the  material  is  composed.  On  porous  materials,  which  may  contain 
sealed  pores,  the  sample  must  first  be  ground  to  a  fine  powder  to 
remove  all  pores..  The  true  specific  gravity  of  the  powder  is  then 
determined  by  means  of  a  specific  gravity  bottle  or  pyenometer.  No 
such  determinations  were  made  for  this  report,  nor  can  they  be 
calculated  from  the  data  available.  In  many  cases,  the  apparent 
specific  gravity  closely  approximates  the  true  specific  gravity. 

Softening  Point. 

The  softening  point  of  a  clay  or  ceramic  mixture  is  defined  as  that 
temperature  (usually  expressed  in  cone  numbers)  at  which  a  standard 
tetrahedron  of  the  clay  when  mounted  and  heated  in  a  manner  here- 
after described,  will  bend  until  it  touches  the  base  upon  which  it 
stands.  The  standard  tetrahedron  is  the  same  size  and  shape  as  the 
small  Orton  standard  pyrometric  cones,  7  mm.  along  the  edge  of  the 
base  and  oO  mm.  high.  The  word  'cone'  is  in  general  use  to  describe 
these  tetrahedra.  The  test  cones  are  mounted  on  a  plaque  of  refrac- 
tory material,  and  are  embedded  not  more  than  2  mm.  in  the  plaque, 
at  an  angle  of  75°  from  the  horizontal. 

The  terms  'fusion  point'  or  'deformation  point'  are  often  used 
interchangeably  with  'softening  point.'  'Fusion  point'  should  be  used 
to  indicate  the  temperature  at  which  complete  loss  of  the  original  shape 
occurs,  and  'deformation  point'  is  best  applied  to  the  temperature  at 
which  alteration  of  the  original  shape  begius. 

The  softening-point  determinations  recorded  in  this  report  were 
made  in  an  oxy-aeetylene  furnace,  after  a  design  by  Hewitt  Wilson.^ 
An  illustration  of  the  furnace  is  given  in  photo  No.  69. 

Six  cones  were  placed  on  each  plaque,  which  were  usually  made 
from  alundum  cement.  The  cones  were  arranged  in  tAvo  rows  of  three 
each,  back  to  back,  and  were  spaced  as  close  together  as  possible.     The 

'  Searle,  op.  cit. 

=  Wilson,  Hewitt.  An  Oxvgen-Acetylone  High-Temperature  Furnace.  Jour.  Am. 
Cer.  Soc,  Vol.  4,  p.  835,  1921. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


247 


four  cones  at  the  corners  were  Orton  standard  cones,  and  tlie  two 
middle  cones  were  of  the  clay  to  be  tested.  Preliminaries  were  first 
run,  with  four  different  standard  cones  in  the  corners,  and  usually 
with  (litferent  unknown  cones  in  tlu'  middh'  positions.  A  tinal  check  was 
always  made  with  two  cdiics  of  the  same  clay  in  tlic  middh'  ])Ositions, 
a  jiair  of  stanchird  cones  ol'  one  number  on  one  side,  and  a  pair  of 
staiulard  cones  of  the  nc.xl  lusher  (or  lowei-)  numbci-  on  the  other  side 
of  the  plaque. 

After  the  tiii-nace  was  heated  to  the  desii'cd  temperature,  each 
fusion  normally  rciiuii'cd  I'loiii  llircc  to  six  minutes.  All  cones  of 
clays  tested   for  this  I'cpcn-t   were  biscuitcd  at   ISOO     F.  Ix'fore  setting 


Photo  No.  tii).      Wilson  oxy-acetylene  c-one  fusion  furnace  in  ceramic  laboratory, 
Stanford  University.      (After  design  of  Prof.  Hewitt  Wilson.) 


in  plaques  for  the  softening-point  determination.  If  this  is  done, 
and  if  the  ])laques  are  dried,  and  pre-heated  by  placing  on  top  of  the 
furnace,  they  may  be  introduced  into  the  hot  furnace  without  danger 
of  s]>alling. 

Tlie  results  are  reported  to  the  nearest  half-cone  number,  using  the 
notation  A-li  {cj/.,  31-;}2)  to  signify  tliat  tlu;  softening  i)oint  lies 
nearer  to  A^  than  to  either  A  or  B.  Closer  estimation,  such  as  A  — , 
A  -|-,  B — ,  or  B  -I-,  was  not  considered  to  be  justified  by  the  limits  of 
accuracy  of  the  method  itself,  and  leads  to  indefiniteness  in  that  such 
notations  might  be  read  to  signify  'less  than'  or  'greater  than,'  without 
setting  the  maximum  or  minimum  range  of  the  values  as  reported. 


248  DIVISION  OP  MINES  AND  MINING 

For  the  purposes  of  tliis  bulletin,  all  clays  havinjj^  a  softening  point 
of  cone  27  or  higlier  are  classified  as  refractory,  and  those  which  fuse 
at  cone  33  or  above  are  considered  to  be  highly  refractory.^ 

Texture,  Structure,  and  Hardness. 

Texture:  Tlie  texture  of  dried  and  fired  test  pieces  is  reported  as 
fine-,  medium-,  or  coarse-grained,  depending  upon  the  average  size 
of  the  grains  in  the  mass,  and  as  close-  or  open-textured,  depending 
upon  the  grading  of  the  grains.  This  classification  is  nsed  in  order  to 
permit  a  distinction  betAveen  those  clays  that  may  contain  a  large 
proportion  of  non-plastic  grains  that  approximate  uniform  size,  and 
those  that  contain  clay  and  graded  non-pla.stic  grains  in  .such  propor- 
tions as  to  give  a  closely  knit,  dense  texture. 

Structure:  The  structure  of  fired  test  ])ieces  is  rei)ortefl  as  granular, 
stony,  homogenous  (with  textural  (|ualifications),  or  heterogeneous 
(with  textural  qnalifications).  The  soundness  of  a  fired  test  piece  is 
indicated  by  such  terms  as  sound,  hair-cracked  (the  development  of 
Avhat  many  ceramic  Avorkers  term  'crow-feet'),  shattered,  or  as  cnn- 
taining  one  or  more  .small  or  large  cracks. 

Hardness:  The  hardness  of  the  fired  test  pieces  is  reported  as  greater 
or  less  than  finger-nail  (==  2|  in  ]\Ioh's  scale)  or  steel  (=  5i  in 
Moh's  scale).  The  hardness  of  dried  clays  is  reported  as  very  soft,  soft, 
medium,  equal  to  the  finger-nail,  or  greater  than  the  finger-nail. 

Color. 

The  natural  and  fired  colors  of  clays  and  ceramic  products  are  too 
often  expressed  in  indefinite  terms  that  can  not  be  duplicated  by  other 
investigators.  Since  the  fired  color  of  a  clay  or  clay  mixture  is  one  of 
its  mo.st  important  properties,  some  standard  scale  of  colors  should  be 
used.  For  that  reason,  more  attention  is  ])ai(l  in  this  work  to  an  accurate 
designation  of  color  than  is  customary  in  similar  publications.  AVhile 
the  colors  obtained  under  laboratory  firing  conditions  are  not  exactly 
the  same  for  each  firing  temjierature  as  Avould  be  obtained  in  commer- 
cial kilns,  the  color  possibilities  of  a  given  clay  are  clearly  indicated 
by  the  laboratory  tests. 

The  two  princi])al  standard  color  scales  in  use  in  the  TTnited  States 
ai'e  the  Ridgway-  and  the  ^lunsell''  systems.*  For  reasons  hereafter 
noted,  the  Ridgway  system  is  used  in  this  bulletin.  Since  this  is,  so  far 
as  is  known,  the  first  time  that  either  system  has  been  used  in  a  bulle- 
tin of  this  nature,  a  brief  explanation  of  color  terms  and  of  each  of  the 
systems  is  given,  together  with  an  approximate  correlation  of  parts  of 
the  two  systems  with  each  other. 

To  adequately  express  a  color,  three  variables  must  be  used  :^  (1) 
Hue,  or  the  series  of  spectrum  colors  and  their  intermediates,  through 


'  Parmelee,  C.  W.,  and  Schroyer,  C.  R.,  op.  cit.,  p.  281. 

=  "Color  Standards  and  Color  Nomenclature."  by  Robert  Ridgway.  I'ublished  by  A. 
Hoen  and  Company,   Baltimore,   Maryland,   l!n2.      Price   $12. 

■■"'A  Color  Notation."  bv  A.  H.  Munsell,  Tth  edition.  1920  (price  $2),  and  "Atlas  of 
the  Mun.sell  System,"  1915  (price  $25),  both  published  l)y  the  Munsell  Color  Company, 
Baltinioi'e,    Maryland. 

■•  Lenchner.  Theodor,  "A  Study  of  Color  and  Its  Appplication  to  Ceramic  Art." 
Jour.  Amer.  Cer.  Soc,  Vol.  10,  p.  538,  July,  1927.  in  which  a  combination  of  the 
Munsell  and  the  Prang   (an  earlier  work)   systems  is  proposed. 

^  In  preparing  this  paragraph,  Munsell's  "A  Color  Notation"  was  freely  drawn  upon. 


CLAY  RESOURCES  AND  (  EKAMIC   INDUSTRY  240 

red.  ormifre,  yellow,  jrreen,  Miic  and  violet.  Hue  can  be  accurately 
expres.sed  by  detenniiiiiijr  tlie  wave  jenji'th  of  tbe  lip-bt  waves  of  each 
color  sensation.  (2)  Tone  or  value,  by  which  a  lijrlit  color  is  distiu- 
g-uished  from  a  dark  one.  When  white  is  added  to  a  color,  various  tints 
result,  and  when  black  is  added,  the  shades  are  in-oduced.  Tone  can  be 
measured  by  nutans  of  a  photometer,  and  is  ex])ressed  scientifically  in 
terms  of  the  amplitude  of  the  light  waves  reflected  by  the  color.  (8) 
Chroma,  by  whieh  stronjr  colors  are  distinguished  from  weak  ones. 
It  is  the  effect  ])roduced  by  addingf  neutral  g:ray  to  a  hue  of  any  given 
tone.  Scientifically,  it  is  the  purity  of  one  wave  leng-th  sei)arated  from 
all  others. 

Ridgwafi  Color  S^tanfhird.'i:  The  key  to  the  Ridgway  classification 
consists  of  36  hues,  which  include  the  six  fundamental  spectrum  colors, 
red,  orange,  yellow,  grreen,  blue,  and  violet,  which  are  connected  by 
intermediate  hues.  The  chromatic  scale  forms  the  horizontal  line  of  the 
entire  series  of  charts.  The  vertical  scale  on  all  charts,  except  the 
carbon-gray  series,  represents  the  tone  (Munsell's  "value")  or  lumi- 
nosity. That  is,  the  proportion  of  black  or  white  which  is  mixed  with 
the  full  color. 

The  first  series  of  Ridgway's  plates  contains  the  pure  colors.  This 
.series  is  repeated  five  times  with  successively  increasing  amounts  of 
neutral  gray,  but  with  some  hues  omitted  in  the  last  three  series.  These 
series  are  designated  "broken  color  scales"  by  Ridgw^ay,  but  Munsell's 
term  "chroma"  is  to  be  ])referred. 

The  complete  designation  of  a  color  from  Ridgway's  charts  therefore 
involves  the  use  of  three  symbols:  (1)  an  arable  numeral  to  designate 
the  hue;  (2)  the  superscript  ('  to  '  '  '  '  ')  to  indicate  the  chroma;  and 
(3)  a  loAver-case  letter  to  designate  the  tone  (or  value).  Thus,  o'k 
is  a  hue  containing  60'';/  red  and  40%  orange,  shaded  with  70.5% 
of  black,  and  the  Avhole  mixed  with  32%  of  neutral  gray.  The  result 
is  a  brick  red.  It  is  possible  to  interpolate  between  the  Ridgway  colors 
whenever  an  exact  match  can  not  be  found,  and  the.se  can  be  designated 
by  the  alternate  symbols  that  are  omitted  from  the  color  charts.  No 
attempt  was  made  to  exi)ress  the  clay  colors  in  this  bulletin  closer 
than  the  nearest  Ridgway  number. 

Expressed  in  common  color  names,  the  Ridgway  hues  1,  3,  5  and  7 
either  of  tone  "b"  or  unaltered  as  to  tone,  are  "red";  9,  11,  13  and  15 
of  the  same  tones  are  "orange";  and  17,  19,  21  and  23  of  the  .same 
tones  are  "yellow."  Colors  that  would  be  classed  as  "pale"  or  "verv 
light"  are  of  tone  "f."  "Pink,"  "light  orange,"  "light  yellow," 
"huff,"  etc.,  are  tone  "d."  The  "i"  tones,  as  well  as  the  "k"  tones 
in  hues  1,  3  and  5,  are  those  that  would  be  designated  as  "dark."  The 
"k"  tones,  except  in  hues  1,  3  and  5,  are  "browns";  for  example,  "red- 
brown.  " '  The  "  m  "  tones  are  ' ' dark-browns. ' '  With  respect  to  chroma, 
the  pure  spectrum  series  is  purer  than  will  be  foimd  in  most  ceramic 
products,  although  many  glazes  fall  into  this  class.  The  (')  series 
includes  most  glazes,  especially  matt  glazes,  as  well  as  the  more  bril- 
liantly colored  red-  and  pink-burning  bodies.  The  (")  series  includes 
the  greater  poi-tion  of  all  pink-,  buff-,  and  red-burned  clay  products. 
The  ('")  series  includes  colors  that  are  generally  too  dull  for  artistic 
purposes.  The  ("")  and  the  ('"")  series  are  decided  grays,  of  little 
interest  in  decorative  wares. 


250  DIVISION  OF  MINES  AND  MINING 

Munsell  Color  Stancla)-ch:  The  Munsell  system  uses  the  conception 
of  a  sphere  to  evaluate  the  tliree  eoh)r  constants.  Each  of  the  con- 
stants is  theoretically  divided  into  ten  equal  parts.  Hue  is  the  hori- 
zontal scale  around  the  circumference  of  the  sphere,  and  is  designated 
by  an  upper-case  letter  represent ing  an  abbreviation  of  the  color,  as 
red  (R),  yellow-red  (YR),  Yellow  (Y),  etc.  These  letters  are  pre- 
ceded by  a  numeral  from  1  to  9  to  represent  the  position  of  the  color  in 
the  scale  of  hues.  For  exami)le,  ".IR"  is  the  ''middle  hue"  of  red. 
These  symbols  are  followed  by  a  fraction,  the  numerator  of  which 
designates  the  value  and  the  denominator  of  which  designates  the 
chroma.  "Value"  is  represented  as  the  vertical  axis  of  the  color  sphere, 
with  white  (value  10)  at  the  top  and  black  (value  0)  at  the  bottom, 
but  samples  are  shown  only  for  values  2  to  9,  inclusive.  "Chroma"  is 
traced  by  radii  at  right  angles  to  the  vertical  axis  of  the  spliere.  An 
approximation  of  Ridgway's  5'k  is  given  in  the  Munsell  system  as 
7R  3/7  but  the  nearest  color  actually  shown  on  the  charts  is  5R  3/7, 
which  lies  between  Ridgway's  I'k  and  I'm. 

Ridgway  vs.  Munsell:  The  Ridgway  system  was  chosen  for  this  work 
in  preference  to  the  Munsell  system  for  the  following  rea.sons:  (1) 
Ridgway's  s.ystera  includes  1115  named  and  systematized  colors, 
whereas  the  Munsell  Atlas  contains  but  340  different  colors,  which, 
liowever,  are  completely  duplicated  in  two  different  arrangements,  and 
})artly  duplicated  in  two  other  arrangements.  (2)  The  Ridgway 
system  has  36  colors  in  the  scale  of  hues,  whereas  the  Munsell  system 
presents  but  10  different  hues.  Each  system  uses  the  same  number  of 
subdivisions  in  the  scale  of  tone.  While  the  Munsell  system  provides 
for  a  maximum  of  10  divisions  of  chroma  compared  to  6  for  the  Ridgway 
charts,  not  all  of  these  divisions  are  used  on  all  tones  and  hues  in  either 
system  and  the  average  chroma  scale  has  approximately  the  same 
number  of  divisions  in  each  system.  As  noted  by  by  Lenchner  ^  the 
Munsell  system  would  be  greatly  improved  by  the  addition  of  more 
hues.  (3)  The  Ridgway  charts  are  bound  in  an  octavo  book,  of 
a]>proximately  one-third  the  bulk  and  weight  of  the  IMunsell  Atlas,  yet 
each  color  has  an  area  of  0.5  sq.  in.,  compared  to  0.4  sq.  in.,  and  the 
minimum  space  between  each  color  sample  is  \  inch,  compared  to  -^ 
inch  on  the  Munsell  charts.  These  are  important  factors  influencing 
the  efficiency  of  use  of  the  two  systems  for  the  purpose  of  matching 
colors.  The  charts  in  either  system  may  be  removed  from  the  book, 
and  mounted  side  by  side  on  a  wall  or  table,  preferably  under  glass. 
In  this  case,  the  Ridgeway  charts  occupy  a  minimum  space  of  10.3 
sq.  ft.,  and  the  Munsell  charts  occupy  11.2  sq.  ft.  When  so  arranged, 
the  Ridgway  system  still  possesses  a  distinct  advantage  in  the  time 
required  to  match  a  color  and  record  it  accurately.  (4)  All  of  the 
Ridgway  colors  are  named,  as  well  as  numbered.  This  is  frequently 
of  value  in  preparing  written  descriptions,  and  for  other  purposes. 
(5)  The  Ridgway  system  costs  less  than  half  as  much  as  tlie  Munsell 
system,  and  there  is  no  difference  in  tlie  life  of  the  colors  when  exposed 
to  light,  lience  replacements  of  RidgAvay's  charts  can  be  made  more 
cheaply  when  the  colors  have  faded. 

A  tabulation  of  the  Ridgway  colors  most  frequently  used  in  this 
report  is  given  in  Table  No.  10,  with  an  approximation  of  the  corres- 

» Ov-  cit. 


CLAY  RESOURCES  AND  CERAMIC  INDITSTRY 


251 


poiiilinji-  Muiisell  color.  This  comparison  was  made  visually  by  three 
persons  '  indei)endentl3%  and  average  values  are  reported.  This  correla- 
tion makes  no  claim  to  scientific  accuracy  but  a])iiroximates  the  result 
that  would  be  obtained  by  the  average  user  of  either  set  of  charts. 


TABLE    No.   10. 
Visual    Correlation    of   Certain    Ridgway    Colors    with    Munsell    Colors. 

Approximate 
Uidgway         Munsell 
.syml)ol         equivalent 


Ai)prt)ximate 

Ai)i)ioximat 

Ridgwa> 

Munsell 

Ridgway 

Munsell 

symbol 

etiuiv 

ilent 

symbol 

equiv 

ilent 

5'i 

7R 

5/9 

3"d 

IR 

7/4 

k 

7R 

3/7 

b 

4R 

6/5 

m 

6R 

3/4 

3R 

5/7 

7'f 

7R 

8/4 

i 

5R 

4/5 

d 

8R 

7/6 

5"f 

3R 

7/3 

b 

8R 

6/8 

d 

5R 

7/4 

9R 

5/8 

b 

5R 

6/5 

1 

9R 

4/7 

_ 

5R 

5/7 

k 

9R 

4/6 

i 

7R 

4/5 

m 

7R 

3/4 

k 

7R 

3/4 

9'f 

8R 

8/4 

m 

7R 

3/3 

d 

9R 

7/5 

7"  f 

6R 

8/3 

b 

lYR 

6/7 

d 

7R 

7/4 

lYR 

6/8 

b 

9R 

6/5 

~i 

2YR 

5/7 

9R 

5/7 

k 

lYR 

5/7 

i 

9R 

4/5 

m 

9R 

3/4 

k 

9R 

4/4 

ll'f 

9R 

8/4 

m 

8R 

3/4 

d 

SYR 

8/r, 

9"f 

6R 

8/4 

b 

SYR 

7/7 

d 

9R 

7>6 

SYR 

6/8 

b 

9R 

6/5 

1 

SYR 

5/7 

9R 

5/6 

k 

4YR 

4/5 

i 

1YR 

5/5 

m 

SYR 

3/5 

k 

lYR 

4/3 

13'f 

5YR 

8/5 

m 

lYR 

3/4 

d 

SYR 

8/5 

n"f 

7R 

8/3 

b 

SYR 

7/7 

d 

2YR 

7/5 

15'f 

4YR 

8/5 

b 

lYR 

6/6 

d 

6YR 

7/7 

_ 

lYR 

5/6 

1) 

7YR 

7/8 

i 

2YR 

5/6 

17'f 

7YR 

8/5 

lS"f 

9R 

8/3 

d 

7YR 

8/5 

d 

SYR 

8/5 

b 

ttYR 

7/8 

b 

SYR 

7/7 

19'f 

5Y 

8/6 

j 

SYR 
SYR 

6/6 
5/6 

l"f 

2R 

7/3 

ir,"f 

9R 

8/4 

d 

8RP 

7/4 

d 

4YR 

8/5 

b 

IR 

7/5 

b 

SYR 

6/6 

3R 

5/5 

4YR 

6/6 

3"f 

3R 

7/3 

i 

5YR 

5/5 

17"f 

2YR   8/4 

d 

GYR   8/4 

b 

7YR    7/7 

_ 

7YR   6/5 

i 

7YR    5/5 

19"f 

7YR   8/3 

d 

9YR   8/5 

b 

9YR   7/7 

9YR   6/7 

1 

9YR  5/6 

l"'f 

6RP   8/2 

d 

6RP  7/4 

b 

9RP   6/4 

5"'f 

9RP   8/2 

d 

9RP  7/3 

b 

3R       6/4 

3R       5/4 

i 

3R       4/4 

9"'f 

4R       8/2 

d 

4R       8/2 

b 

4R       6/4 

6R       5/4 

i 

8R       4/4 

k 

8R       3/4 

lS"'f 

5R       8/1 

d 

5R       8/2 

b 

7R       7/3 

lYR   5/4 

1 

2YR   4/4 

k 

3YR    4/3 

17"'f 

SYR   8/2 

fl 

SYR   7/3 

b 

4YR   6/3 

7YR    6/3 

i 

7YR   5/3 

k 

SYR   4/2 

L'l"'f 

4Y       8/2 

d 

6Y       8/3 

Color  Classification  of  Clays:  The  clays  desci'ibed  in  this  report  are 
classified  as  to  color  into  four  groups,  following  Parmelee  and  Schroyer," 
but  definitely  fixing  the  boundaries  of  each  group  by  the  use  of  Ridg- 
way's  colors.     The  classification  is  as  follows: 

I.  Clays  Burning  White  or  Cream  Colored,  not  Calcareous.  Into 
this  group  are  placed  all  clays  that  fire  at  the  highest  firing  tempera- 
tures used,  to  tones  nearer  to  white  than  Ridgway 's  "f "  tones.  There 
is  need  for  an  extension  of  standard  color  nomenclature  into  this  range," 
but  in  lieu  of  a  well-established  system,  the  terms  "yellowish-  white," 
"pinkish-white,"  "grayish-white,"  etc.,  are  used  in  this  report.  All 
of  the  clays  in  this  group  lire  to  colors  that  are  sufficiently  good  to 
permit  the  use  of  the  clay  in  stoneware  bodies,  most  of  them  can  be 
used  to  some  extent  in  sanitary  ware  and  electrical  porcelain,  if  other 


1  Prof.  F.  G.  Tickell,  Stanford  University,  Mrs.  Bernice  L.  Tickell,  and  the  author. 

=  Parmlee,  C.  W.,  and  Sohroyer,  C.  R.,  "Further  Investigations  of  Ulinoi.s  Fire 
Clays,"  111.  Geol.   Surv.  Bull.  No.   38,  p.   278. 

'  See  in  this  connection  :  Lofton,  R.  E.,  A  Measure  of  the  Color  Characteristics  of 
WHiite  Papers,  U.   S.  Bur.   Std.  Tech.  Paper  244,   192S. 


252  DIVISION  OF  MINES  AND  MINING 

properties  are  suitable,   and   a   few  are  -\vliite  enoii<i]i   for  nse,  when 
washed  free  from  sand,  in  phice  of  En<«:lish  china  clay. 

II.  Buff-Burninp:  Clays.  Into  this  class  are  ])laced  all  clays  that  fire 
to  tones  corresponding  to  Ridgway's  "f"  tones,  all  "d"  tones  from 
hue  9  to  19,  inclnsive,  and  all  "b"  tones  from  hue  15  to  19,  inclusive. 
Exceptions  are  noted  in  group  IV. 

III.  Clays  Burning  Red,  Brown,  or  Other  Dark  Colors.  Into  this 
group  are  placed  all  clays,  excepting  those  of  group  IV,  that  fire  to 
colors  darker  than  those  of  group  II. 

IV.  Clays  burning  Dirty  White,  Cream  White,  or  Yellowish  White. 
The  clays  of  this  group  are  mainly  calcareous  or  magnesian,  and  color 
is  not  an  important  criterion. 

Chemical  Analysis. 

The  relative  value  of  chemical  analyses  in  the  study  of  clays  has  been 
well  summarized  by  Hewitt  AVilson^  as  follows : 

"Chemical  analysis  provides  its  most  effective  usefulness,  in  the  case  of  the  high- 
grade  clays,  in  estimating  the  degree  of  purity  of  the  white-burning,  kaolin-like 
materials  and  the  alumina-silica-fiux  ratio  in  the  fire  clays,  but  in  the  case  of  the 
red-  and  brown-burning  structural-ware  clays,  the  impurities  furnish  the  most 
important  data.  We  can  but  guess  the  fired  color,  strength,  shrinkage,  porosity, 
and  vitrification  range  from  the  analytical  data  and  for  these  properties,  must  rely 
on  practical  firing  tests.  If  the  chemical  analysis  is  complete,  however,  it  gives  a 
good  idea  of  the  troublesome  materials  present,  i.e..  those  which  cause  early  fusion, 
short  vitrification  range,  scumming,  and  troublesome  gases  which  delay  oxidation. 
It  happens  that  the  usual  commercial  chemical  analysis  does  not  include  carbon  and 
sulphur  and  other  troulilesome  im])urities  except  when  combined  with  water  of 
chemical  combination  and  called  'ignition  loss'  or  'volatile  matter.'  Likewise,  a 
complete  chemical  analysis  of  the  complicated  silicate  mixture  called  'clay'  is  a 
difficult  analytical  procedure,  and  many  hundreds  of  the  analyses  are  inaccurate. 

"In  studying  clays  of  the  whiteware  and  fire-clay  type,  a  knowledge  of  the 
chemical  composition  is  always  desirable,  but  it  must  l^e  assigned  a  secondary  value 
because  of  the  infiuence  and  modification  of  the  physical  iirojierties.  Clays  of  the 
fire-clay  type  must  primarily  have  a  composition  corresjionding  to  refractory  chiys. 
But  this  is  not  enough.  For  instance,  there  are  in  the  United  States  a  large  number 
of  clays  of  practically  the  same  composition  as  the  imported  European  plastic  fire 
clays,  so  highly  prized  for  glass-pot,  brass,  and  steel-crucible  work,  Ijut  which  fail 
completely  in  satisfying  the  physical,  dry,  and  fired  requirements.  A  cone  fusion  test 
costs  less  in  time  and  money  than  a  chemical  analysis.  The  best  way  to  determine 
the  refractory  value  of  a  clay,  having  given  only  the  chemical  analysis,  is  to  trans- 
late it  to  terms  of  cone  fusion. 

"When  physical  tests  of  clay  bodies  are  not  satisfactory  and  changes  are  desired, 
the  chemical   analysis  will  often  locate  the  trouble  and  indicate  the  proi)er  remedy." 

Relatively  few  chemical  analyses  were  made  for  the  ])urpose  of  this 
report.  A  few  typical  samples  were  selected  from  those  clays  whose 
ceramic  pro])erties  were  studied  in  the  laboratory,  and  analyses  were 
made  in  the  Stanford  University  ceramic  laboratory,  using  the  methods 
recommended  by  the  American  Ceramic  Society."  Practically  all  of 
these  analyses  were  made  in  duplicate  or  triplicate,  and  exceptional 
])recautions  were  taken  to  insure  accuracy,  especially  in  the  determina- 
tions of  alumina  and  silica,  which  are  so  often  inaccurately  rejiorted. 
A  few  analyses  of  laboratory  samples  were  made  by  K.  W.  Baum,  of 
the  Stevenson  Engineering  Company.  Analyses  of  various  California 
clays  were  submitted  by  some  of  the  clay  manufacturers  in  the  state, 
or  were  found  in  the  literature.  Where  these  a]iply  to  definite  clay 
beds  that  were  sampled  by  the  author,  the  analyses  are  included  under 
the  clay  sample  number  to  which  they  refer.  It  must  be  understood, 
however,  that  such  analyses  were  not  made  on  the  same  sam])le  as  that 
which  was  tested  in  the  laboratorv,  lienee  some  of  tliem  do  not  correlate 


'Ceramics,  pp.   45-4f..      McOraw-Hill  Book  Co.,   1927. 

=  Report  of  the  Committee  on  Standards,  Amer.  Cer.   Soc,  reprint   from  Yearbook, 
1921-1922. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  253 

very  well  with  the  cei'ainic  pfdiK-iiics  noted.  Another  i^roup  of 
analyses  is  inelnded  of  elays  not  slndii'd  l)y  the  author.  ]\Iost  of  these 
are  from  the  S;ni  Joa(|uin  \'alh'y,  and  were  coiil  i-ihnted  by  K.  W. 
Bauni. 

For  convenience  of  reference,  the  analyses  are  f^rouped  according 
to  the  clay  classification  used  in  this  report,  and  are  to  be  found  near 
the  end  of  Chaptei-  V. 

Classification  of  Clays. 

Tlie  clay  classification  used  in  this  report  is  essentially  that  of 
Parmelee,^  but  is  presented  in  a  simplified  form.  This  classification  is 
based  upon  the  physical  properties  that  determine  the  important  uses 
of  a  given  clay.  The  modified  classification  follows,  witli  notations  to 
correlate  it  Avith  that  of  Parmelce. 


I.  CLAYS    BURNING    WHITE   OR   CREAM    COLORED,   NOT   CALCAREOUS." 

A.  Open-burning  clays,  i.e.,  having  an   apparent  porosity  of  6%   or 

more  at  cone  15. 

The  dividing  line  between  oi)en-burning  and  dense-burning  clays  is 
placed  at  5%  in  Par  melee's  classification.  In  this  report  the  dividing 
line  is  at  6%  in  order  to  make  some  allowance  for  the  more-rapid  firing 
cycle  used. 

Parmelee  states  "still  distinctly  ijorous  at  cone   15." 

1.  Low  strength,  dry  modulus  less  than  200  lb.  per  sq.  in.,  e.g., 

residual  kaolins  and  sandy  fireclays. 

It  is  not  clear  whether  Parmelee  intends  to  include  sandy  fireclays  in 
this  gi'oup. 

2.  Medium  and  high  .strength,  dry  modulus  exceeding  200  lb. 

])er  sq.  in.,  e.g.,  secondary  kaolins. 

Open-burning  clays  are  valuable  in  the  manufacture  of  pottery 
becau.se  of  good  color  or  good  strength  and  good  color.  They  are  often 
highlv  refraetorv,  and  mav  be  of  value  for  special  refractories. 

B.  Clays   burning   dense,   i.e.,   have  less   than   6%    apparent   ])orosity 

between  cones  10  and  15. 

Parmelee  states  "becoming  nearly  or  completely  non-porous  between  cones  10 
and  15." 

3.  Generally,  but  not  always,  refractory. 

Parmelee  divides  this  group  into  three  subdivisions,  as  follows: 

"a.   Non-refractory  clays. 

"3.   Good   color,   medium   to  high   strength,   medium   shrinkage.      Uses:   Pottery, 

including  certain  whiteware,  porcelain,  stoneware. 
"4.   Poor  color,  medium  to  high  strength,  medium  shrinkage.     Uses:   Stoneware, 

terra  cotta,  abrasive  wheels,  zinc  retorts,  face  brick,  saggers. 

"b.   Refractory  clays. 

"5.  Good  color,  medium  to  high  strength,  medium  shrinkage.  Uses  :  Refractor- 
ies, especially  for  glass,  if  they  do  not  overburden  seriou.sly  for  5  cones 
higher.     Also  uses  as  stated  in  Parmelee's  No.   3." 


'  Parmelee,  C.  W.,  and  Schroyer,  C.  R.,  Further  Investigations  of  Illinois  Fire  Clays, 
111.  Oeol.  Surv.  Bull  No.  38,  pp.  278-9,  1922. 

^'The  color  limitations  used  in  this  report  are  given  on  page  251. 


254  DIVISION  OF  MINES  AND  MINING 

C.  Dense-burning  clays,  i.e.,  Iiavini^  less  than   6/^    apparent  ])orosity 
between  cones  5  and  10. 

Parmelee  states  ".  .  .  become  nearly  or  completely  iioii-pni-inis  between  cones 
5  and  10  and  do  not  ovei'burn  seriously  at  5  cones  higher  than  the  Itmperatiire  at 
which  minimum  porosity  is  reached." 

4.  Generally,  but  not  always,  refractory. 
Parmelee  divides  this  group  into  five  classes,  as  follows: 

"a.   Non-refractory  clays. 

"6.  Good  color,  medium  to  high  strength,  medium  shrinkage,  usually  reach 
minimum  porosity  between  cones  .5  and  8.  Type:  Ball  clays.  U.ses : 
I'ottery,  whiteware,  porcelain,  and  stoneware. 

"7.   Poor   color,    medium   to   high   strength,   medium   shrinkage.     Uses :   Stoneware, 

terra  cotta,  abrasive  wheels,  zinc  retorts,  face  brick,  saggers, 
"b.   Refractory   clays. 

"S.   Non-porous  or  practically  so  at  cone   .'>  ;   do   not   seriously  overburn   for   12 

cones   higher;    highly   refractory;   softening   point   at  cone   :il    or   higher; 

bending  strength   minimum   325   pounds  per  square  inch.      Use:   Graphite 

crucibles  for  melting  brass, 
"fl.   Non-porous  at  about  1275°  C.   (cone  8),  not  overflring  at  1400°  C.  or  higher. 

Strength   and   softening  point   as   alaove.      Use  :   Steel   crucibles. 

"10.  Become  dense  at  about  1275°  C.  (cone  8).  Do  not  overburn  below  1425°  C. 
Bonding  strength,  250  pounds  per  square  inch  or  higher.  Softening  point, 
cone  29  or  higher.      Use  :   Glass  pots." 

II.   BUFF-BURNING   CLAYS. 

A.  Refractory  clays  (softening  point,  cone  27  or  above). 

a.  Open-burning,  i.e.,  having  a  porosity  of  6%  or  more  at  cone  15. 

Parmelee  states  ".     .     .     porosity  of  5%  or  more  at  cone  15  or  above." 

5.  Low  strength.     Usually  higli  in  non-])lastic  material. 

6.  ]Medium  and  high  strength. 

Parmelee  uses  four  subdivisions  to  cover  (5)  and  (6)   as  follows: 

"Indurated — non-plastic  or  slightly  plastic  unless   it   lias   been  weathered. 

Type  :   Flint  clay. 
"11.   Normally  aluminous;  maximum  alumina  40%.     Uses:   Refractories. 
"12.  Highly    aluminous;    alumina    exceeds    40%.      Type:  Diaspore   clay.      Uses; 

Refractories,  abrasives. 

Plastic. 
"13.  Normally  siliceous;   maximum   silica   not  exceeding   65%.     Uses:  Firebrick 
and    other    refractory    wares,    terra    cotta,    sanitary    ware,    glazed    and 
enameled  brick   (see  specific  requirements). 

"14.  Siliceous;  having  a  silica  content  above  659^.  Type:  Many  of  the  New 
Jersey    Are    clays.      Uses :   Firebrick    and    other    refractories." 

b.  Dense-burning  between  cones  10  and  15,  i.e.,  attaining  an  appar- 

ent porosity  of  6%  or  less  within  that  range. 

Parmelee  states  "...     a  minimum  porosity  of  5%   or  less     .     .     ." 

7.  Generally  medium  to  high  strength. 

This  is  Parmelee 's  class  15,  and  is  explained  as  follows: 

"15.  Medium  to  high  strength.  Do  not  overburn  for  5  cones  higher  than  point 
of  minimum  porosity.  Uses :  Glass  pots  and  other  refractories ;  al.so 
used  for  firebrick,  saggers  and  miscellaneous  refractories,  architectural 
terra  cotta,  sanitary  ware,  enameled  and  face  brick." 

e.  Den.se-burning,  i.e.,  attaining  a  porosity  of  6%  or  less  at  cone 
10  or  lower. 

Parmelee  states  "...     a  porosity  of  5%  or  less     .     .     ." 

8.  Generally  medium  to  high  strength. 

Parmelee  divides  this  grouj)  into  three  classes,  as  follows : 
"16.  See   (Parmelee's)      8. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  255 

"17.   See    (Parnielee's)      9. 

"18.   See    (Tarmelee's)    10. 

"These  tliree  classes,  10,  17  and  18,  are  used  also  for  ziiie  retorts,  firebrick, 
saggers,  and  miscellaneous  refractories,  architectural  terra  cotta,  sani- 
tary ware,  enameled  and  face  brick." 

B.  Xon-refrac'tory  clays. 

a.  Open-bnrniiijr,  i.e.,  do  not  attain  a  porosity  of  fi'^J   or  less  at  any 

cone  lower  tlian  cone  10. 

rarmelee  states  "...      a  porosity  of   5'/^    or  less 

!i.  lli<.>-h  or  medium  streiioth.      Uses:  Architectural  terra  cotta, 
stoneware,  yellow  ware,  face  brick,  sanitary  ware. 

10.  Low  strength.     Use :  Brick.  ' 

Classes  (fl)  and  (10)  correspond  to  Parnielee's  19  and  20, 
respectively. 

b.  Dense-burning,  i.e.,  attain  an  ajiparent  ])orosity  of  less  than  6% 

at  cones  lower  than  10. 

Parmelee  states  "...     a  porosity  of  les.s  than   5%     .     .     ." 

11.  Generally  medium  or  high  strength. 

This  is  Parnielee's  class  21,  and  is  described  as  follows: 

"21.  High    or    medium    strength.      Uses:  Architectural    terra    cotta,    stoneware, 
abrasive  wheels,  sanitary  ware,  face  brick,  paving  brick." 

III.  CLAYS  BURNING  RED,  BROWN,  OR  OTHER  DARK  COLORS. 

A.  Open-burning  clays,  i.e.,  those  that  do  not  attain  an  apparent  i)or- 

osity  of  6%  or  less  at  any  temperature  short  of  bloating  or  fusion. 

Parmelee  states  ".  .  .  do  not  attain  low  porosity  at  any  temperature  short  of 
actual   fusion." 

12.  ]\ledium  or  high   strength.      Uses:  Brick,   drain   tile,  hollow 

blocks,  flower  pots,  pencil  clays,  ballast. 

1.3.  Low  strength.     Use:  Brick. 
Classes     (12)     and     (13)     correspond    to    Parnielee's    22    and    23, 
respectively. 

B.  Dense-burning  clays,  i.e.,  those  that  attain  an  apparent  jiorosity  of 

6%  or  less  at  any  temperature  short  of  bloating  or  fusion. 

Parmelee  makes  no  special  statement  to  qualify  the  meaning  of 
"Dense  burning,"  but  the  definition  follows  from  IIT-A,  above. 

a.  Having  a  long  vitrification  range  (4  cones). 

Parmelee  requires  a  5-cone  vitrification  range,  but  the  data  of  this 
bulletin  do  not  permit  such  a  .segregation,  as  only  alternate  cone  num- 
bers were  studied. 

14.  Generally  medium  or  high  strength.  Uses,  if  medium  or  high 
strength :  Conduits,  sewer  pipe,  face  brick,  roofing  tile, 
paving  brick,  promenade  tile,  architectural  terra  cotta,  and 
similar  ware.  If  low  strength:  Common  brick,  floor  tile, 
dust  body  in  various  wares. 


256  DIVISION  OF  MINES  AND  MINING 

Parmeloo  makes  two  classes,  24  and  25,  divided  as  to  medium  to  hif?h 
strength  or  low  strength,  with  the  uses  practically  as  indicated  above. 

b.  Having  a  short  vitrification  range  (less  than  -i  cones). 

15.  Generally  medium  to  high  strength.      Uses:  Common  brick, 
face  brick,  hollow  tile,  flower  pots. 

Tliis  is  Parmelee's  class  26,  described  as  "High  or  medium  strength," 
witii  the  same  uses  as  given  above. 

c.  Fusing  at  a  low  temjjeraturc,  api)roximately  cone  5,  to  foi-m  a 
glass. 


&^ 


16.  Slip  clays. 

This  is  Parmelee's  class  27.  No  clays  were  found  in  California  in 
this  class,  but  room  is  left  in  the  classification  in  case  any  are  found  in 
the  future. 

IV  CLAYS    BURNING    DIRTY    WHITE,   CREAM    WHITE,   OR    YELLOWISH 

WHITE. 

17.  Generally    containing    calcium    or    magnesium    carbonate    or 

both.     Seldom  reach  very  low  porosity.     Have  a  very  short 
heat  range.     Use :  Common  brick,  or  may  be  worthless. 

This  is  essentially  Parmelee  's  class  28,  which  is  described  as  follows : 

"28.  Containing  calcium  or   magnesium   carbonate  or   both.     Never   reach   very 
low  porosity.      Have  a  very  short  heat  range.      Use  :   Common   brick." 

The  foregoing  classification  is  not  presented  as  being  preferable  for 
general  use  to  Parmelee's  more  complete  one,  but  it  serves  the  i)ur- 
poses  of  this  bulletin  better,  in  that  the  tests  on  the  California  clays 
were  not  sufficiently  comprehensive  to  permit  the  degree  of  refinement 
of  clay  classification  that  characterizes  Parmelee  and  Schroyer's  report. 
For  example,  bonding-strength  determinations  are  necessary  in  order 
to  segregate  Parmelee's  classes  8,  9  and  10,  and  16,  17  and  18;  firing 
tests  to  cone  19  or  20  are  necessary  to  fully  determine  the  properties 
of  a  clay  for  his  classes  5,  8  and  16 ;  chemical  analj^ses  are  necessary  in 
order  to  segregate  his  classes  11,  12,  13  and  14,  and  firing  to  each  cone 
number,  instead  of  to  alternate  cone  numbers,  is  required  in  order  to 
separate  the  red-burning  clays  having  a  long  vitrification  range  from 
those  having  a  short  range.  To  complete  the  data  for  a  satisfactory 
allocation  of  clays  according  to  Parmelee's  classification,  would  have 
required  more  than  twice  the  amount  of  work  than  that  represented  by 
the  testing  for  this  bulletin,  without  considering  the  extra  field  work 
that  should  be  entailed  to  secure  thoroughly  representatiA'e  samples  of 
entire  clay  beds.  It  is  questionable  if  50-pound  field  samples,  unless 
obtained  by  quartering  down  a  number  of  larger  channel-cut  samples, 
or  by  combining  a  number  of  coredrill  samples,  are  sufficiently  reliable 
to  warrant  more  elaborate  tests  than  have  been  made. 


»i-.T:in       i  -NTl-*     /ir-D  A  HTK'     T  M  HT  T>iTR  V  Ji'^l 


ed.  The 
:'y  trans- 
he  clays 
ord  IJiii- 
11(1  dried 
v'ho  ^vish 
ew  clays 
)spectin<i,' 

that  are 
Lii  plastic 
a.  Tests 
data  are 
)  class  1, 
davs  antl 
Wilson.  1 
the  clay 
)n  of  the 


vYS. 

15. 


.  "E-101 
is  princi- 
ns  33.0% 
e  enough 
len  fired. 
,  and  the 
Dry  and 
e  cone  1, 
f"  tints, 
the  hard- 
^e,  plastic 
-29.  The 
)e  washed 
specking, 
:  vitrifica- 
ni  found, 

).  "E-102 
but  is  of 
the  fired 
colors  are  darker.     The  percentage  remaining  on   2UU-mesh  is  22.6. 

'  The  Clays  and  Shales  of  Washington,  Their  Technology  and  Uses.     Bull.  Univ.  of 
Wash.,  Engin.  Exp.  Sta..  No.  18,  p.  203,  ct  seq. 

17 — .'')4979 


256  DIVISION  OP  MINES  AND  MINING 

Panneloo  makes  two  classes,  24  and  25,  divided  as  to  medium  to  hig-h 
streiiKtIi  or  low  strength,  with  the  uses  praetieally  as  indicated  above. 

b.  Having  a  short  vitrification  range  (less  than  4  cones). 

15.  Generally  medium  to  high  strength.      Uses:  Common  brick, 

face  brick,  hollow  tile,  flower  pots. 

Til  is  is  Parmelee's  class  26,  described  as  "High  or  medium  strength," 
witii  the  same  uses  as  given  above. 

c.  Fusing  at  a  low  temperature,  ap|)r()xiiiuite]y  cone  5,  to  form  a 

glass. 

16.  Slip  clays. 

This  is  Parmelee's  class  27.  No  clays  were  found  in  California  in 
this  class,  but  room  is  left  in  the  classification  in  case  any  are  found  in 
the  future. 

IV  CLAYS    BURNING    DIRTY    WHITE,   CREAM    WHITE,   OR    YELLOWISH 

WHITE. 

17.  Generally    containing    calcium    or    magnesium    carbonate    or 

both.     Seldom  reach  very  low  porosity.     Have  a  very  short 
heat  range.     Use :  Common  brick,  or  may  be  worthless. 

This  is  essentially  Parmelee's  class  28,  which  is  described  as  follows: 

"28.  Containing  calcium   or   magnesium   carbonate   or   botli.     Never   reach   very 
low  porosity.      Have  a  very  short  heat  range.      Use  :   Common   brick." 

The  foregoing  classification  is  not  presented  as  being  preferable  for 
general  use  to  Parmelee's  more  complete  one,  but  it  serves  the  i)ur- 
poses  of  this  bulletin  better,  in  that  the  tests  on  the  California  clays 
were  not  sutBciently  comprehensive  to  permit  the  degree  of  refinement 
of  clay  classification  that  characterizes  Parmelee  and  Schroyer's  report. 
For  example,  bonding-strength  determinations  are  necessaiy  in  order 
to  segregate  Parmelee's  classes  8,  9  and  10,  and  16,  17  and  18;  firing 
tests  to  cone  19  or  20  are  necessary  to  fully  determine  the  properties 
of  a  clay  for  his  classes  5,  8  and  16 ;  chemical  analj^ses  are  necessary  in 
order  to  segregate  his  classes  11,  12,  13  and  14,  and  firing  to  each  cone 
number,  instead  of  to  alternate  cone  numbers,  is  required  in  order  to 
separate  the  red-burning  clays  having  a  long  vitrification  range  from 
those  having  a  short  range.  To  complete  the  data  for  a  satisfactory 
allocation  of  clays  according  to  Parmelee's  classification,  would  have 
required  more  than  twice  the  amount  of  work  than  that  represented  by 
the  testing  for  this  bulletin,  without  considering  the  extra  field  work 
that  should  be  entailed  to  secure  thoroughly  representative  samples  of 
entire  clay  beds.  It  is  questionable  if  50-pound  field  samples,  unless 
obtained  by  quartering  down  a  number  of  larger  channel-cut  samples, 
or  by  combining  a  number  of  coredrill  samples,  are  sufficiently  reliable 
to  warrant  more  elaborate  tests  than  have  been  made. 


Photo  No.  711.      Cabinet  of  fired  test  pieces,  ceramic  laboratory,  .Stanford  University. 


54979 — facing  iiage  257 


256 

Parmelee  mak 
strenytli  or  low 

b.  Having  j 

15.  Genei" 

face 

This  is  Parme 
with  the  same  ii 

c.  Fusing  a 

glass. 

16.  Slip  el 

This  is  ParnK 
this  class,  but  ix 
the  future. 

IV  CLAYS    BUR^ 

17.  Generf 

both 
heat 

This  is  essenti 

"28.   Containlr 
low  poi 

The  foregoing 
general  use  to  '. 
poses  of  this  bu 
were  not  suffieie 
of  clay  classifica 
For  example,  b( 
to  segregate  Pai 
tests  to  cone  19 
of  a  clay  for  his 
order  to  segrega 
number,  instead 
separate  the  red 
those  having  a  ! 
allocation  of  cla 
required  more  tl 
the  testing  for  1 
that  should  be  e 
entire  clay  beds 
obtained  by  qua 
or  by  combining 
to  warrant  more 


CLAY  RESOURCES  AND  CERAMir  TXDUSTRY  257 

Chapter  V. 

RESULTS  OF  LABOKATORY  TP]STS. 

Table  No.  11  is  a  complete  classified  list  of  all  samples  tested.  The 
fired  test  i)ieces,  samples  of  dried  bars  fsalvaf^ed  from  the  dry  trans- 
verse-.stren<?tli  tests),  and  lumj)  and  f^round  sam])les  of  all  the  clays 
are  kept  in  an  accessible  file  in  the  ceramic  laboratory  at  Stanford  Uni- 
versity. Photo  No.  70  shows  the  case  eontainin*?  the  fired  and  dried 
test  pieces.  These  files  may  be  of  interest  to  clay  workers  who  wish 
to  select  clays  for  specific  purposes,  and  it  is  hoped  that  new  clays 
can  be  added  from  time  to  time  as  they  are  disclosed  in  i)i'ospectin<»' 
and  mining  operations. 

Tests  are  included  on  two  clays  from  outside  of  the  state  that  are 
being  used  in  local  plants.  These  are  No.  56  in  class  7,  a  German  plastic 
fireclay,  and  No.  59  in  class  2,  the  Edgar  kaolin  from  Florida.  Tests 
were  made  on  English  china  and  ball  clay  but  the  detailed  data  are 
not  included  herein.  The  china  clay  was  found  to  belong  to  class  1, 
and  tlie  ball  clay  belongs  in  class  4.  The  data  on  tlie  English  clays  and 
the  Edgar  kaolin  correlate  closely  with  tliose  given  by  Hewitt  Wilson.' 

The  page  numbers  cited  in  the  descriptive  text,  following  the  clay 
sample  nundjer,  refer  to  the  pages  containing  the  description  of  the 
deposit  from  whicli  the  sample  was  taken. 

I.   WHITE-   OR  CREAM-BURNING    NON -CALCAREOUS  CLAYS. 
A.  Open- Burning,  More  Than  6%  Apparent  Porosity  at  Cone  15. 

1.  Low  Strength. 

No.  11  (p.  168).  Riverside  County.  Alberhill  C.  &  C.  Co.  "E-101 
China  Clay."  This  is  a  sandy  clay  of  the  kaolin  type,  and  is  princi- 
pally used  in  stoneware  bodies.  See  also  No.  12.  It  contains  33.0% 
of  4"  200-mesh  sand,  which  is  mainly  quartz,  but  there  are  enough 
ferro-magnesian  minerals  to  cause  red  and  black  specks  when  fired. 
The  plasticity  is  good,  though  short,  the  dry  strength  is  low,  and  the 
dry  condition  is  weak,  crumbly  and  sandy.  The  colors  are:  Dry  and 
w^et,  yellowish  white;  from  cone  010  to  cone  1,  13"f;  above  cone  1, 
butf-white,  considerably  nearer  to  white  than  Ridgway's  "f"  tints. 
Finger-nail  hardness  is  developed  at  cone  04,  and  at  cone  13  the  hard- 
ness is  still  slightly  less  than  steel.  The  total  linear  shrinkage,  ])lastic 
basis,  at  cone  15,  is  11.4%.  The  softening  point  is  cone  28-29.  The 
best  firing  range  is  from  cone  3  to  cone  13.  The  clay  covdd  be  washed 
to  remove  non-plastic  impurities,  which  Avould  eliminate  the  specking, 
and  increase  the  plasticity  and  strength,  as  well  as  lower  the  vitrifica- 
tion point,  but  as  no  large  bodies  of  this  variety  have  been  found, 
washing  at  the  mine  is  not  warranted. 

No.  12  (p.  163).  Riverside  County.  Alberhill  C.  &  C.  Co.  "E-102 
China  Clay."  This  is  .similar  in  eA'ery  respect  to  No.  11,  but  is  of 
slightly  poorer  quality,  as  it  contains  more  impurities,  and  the  fired 
colors  are  darker.     The  percentage  remaining  on  200-mesh  is  22.6. 

>  The  Clays  and  Shales  of  W'ashington,  Their  Technology  and  Uses.  Bull.  Univ.  of 
Wash.,  Engin.  Exp.  Sta.,  No.  IS,  p.  20.3,  ct  seq. 

17—54979 


258 


DIVISION  OP  MINES  AND  MINING 


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CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  259 

Finger-nail  liardness  is  developed  at  cone  02,  and  knife  hardness  at 
cone  12.  The  total  linear  slii-inkaue,  plastic  basis,  at  cone  12  is  12.2%. 
The  softeninj;  point  is  cone  2()-27.  The  best  firing  range  is  from 
cone  3  to  cone  ]:]. 

No.  37  (p.  201).  San  Diego  ("oiinty.  El  ("ajon  Mountain.  The 
sample  is  rejiresentative  of  the  more  kaolinitic  ])liase  of  a  residual 
kaolin  dejiosit,  of  which  No.  38  is  a  more  general  sam])le.  It  is  not 
entirely  free  from  fine  (piartz  and  feldsi)ar  grains,  and  also  contains 
some  ferro-magnesian  minerals  whicli  ajjjjcar  as  numerous  black 
specks  in  the  fired  clay.  The  proi)ortion  of  +  200-mesh  sand  is  13.0%. 
The  i)lasticity  is  workable,  but  is  weak  and  sticky.  The  dry  strength 
is  medium  low,  and  in  the  dry  state  the  sample  is  soft  and  crumbly. 
Slow  drying  is  necessary  to  avoid  drying  cracks.  The  colors  are  nearly 
white,  with  a  ])inkish  tinge  at  low  cone  numbers,  and  a  yellowish  tinge 
when  fired  above  cone  1.  Finger-nail  hardness  api)ears  below  cone  010, 
and  steel  hardness  at  cone  1.  Fine  cracks  ai)pear  at  high  tem])eratures. 
The  total  linear  shrinkage,  ])lastic  basis,  at  cone  15,  is  20.9'/  .  The 
softening  point  is  cone  34.  This  clay  could  be  washed  to  remove  the 
ferro-magnesian  minerals,  but  the  deposit  is  too  small  and  irregular, 
and  too  isolated  for  co)nmercial  operations.  It  was  at  one  time  mined 
on  a  small  scale  and  the  clay  was  used  in  the  manufacture  of  Faience 
tile,  and  some  attemi^ts  were  made  to  use  the  material  as  a  substitute 
for  English  china  clav  in  whiteware  bodies. 

No.  38  (p.  201).  San  Diego  County.  El  Cajon  IVIountain.  This  is 
a  general  sam])le  of  the  residual  kaolin  dejiosit  from  which  sample 
No.  37  was  taken.  It  contains  57.0' ;  of  +  200-mesli  grains,  most  of 
which  are  undecom])()sed  (puirtz  and  feldsi)ar,  but  there  is  a  smaller 
proportion  of  ferro-magnesian  minerals  than  in  sample  No.  37.  It 
effervesces  slightly  in  hydrochloric  acid.  The  plasticity  is  poor,  the 
dry  strength  is  nu'dium  ]ow%  and  the  dry  and  fired  structure  is  coarse 
and  granular.  The  colors  closely  approximate  white,  with  a  faint  ])ink 
hue.  Steel  hardness  is  not  developed  at  cone  13.  The  total  linear 
shrinkage,  i)lastic  basis,  at  cone  13,  is  4.75%.  The  softening  point  is 
cone  32-33.  The  best  structure  and  color  is  obtained  by  firing  above 
cone  7.  The  amount  of  kaolin  thai  could  be  extracted  by  wasliing  was 
not  determined,  but  not  over  20%  could  be  expected. 

No.  62  (i).  145).  Orange  County.  East  of  San  .Juan  Capistrano, 
on  the  O'Neill  rancli.  "White  bone."  This  is  a  ])lastic  fireclay  that 
usually  contains  over  45/{  of  alumina.  Although  the  pisolitic  struc- 
ture of  tlie  raw  clay  is  lacking,  or  is  but  poorly  (Un'elo])ed,  it  may  be 
classed  as  a  bone  clay  on  account  of  its  high  alumina  content,  and  its 
ceramic  properties.  The  ])lasticity  is  short,  the  dry  strength  is  low, 
and  the  dry  condition  is  medium  hard,  medium-grained,  and  open- 
textured.  The  residue  on  200-mesh  is  46.4%.  The  colors  are  nearly 
white  througliout,  with  a  pink  hue  at  low  firing  temperatures,  changing 
to  yellowish  white  at  higher  firing  temperatures.  Scattering  yellow  and 
brown  iron  specks  ai)i)ear  at  high  tem])eratures.  Finger-nail  hardness 
is  obtained  below  cone  010,  and  steel  hardness  develops  at  cone  1.  Light 
crow-foot  cracks  appeared  in  all  jiieces  fired  above  cone  1.  The  fired 
texture  is  granular  and  open.  The  total  linear  shrinkage,  plastic 
basis,  at  cone  15,  is  17.5 ^r .     The  softening  point  is  cone  34.     The  best 


260  DIVISION  OP  MINES  AND  MINING 

firing  range  is  above  cone  1,  and  well  vitrified  structures  are  obtained 
at  cone  11  or  above. 

No.  6:K  61  and  ;:268  (p.  140).  Orange  County.  12  m.  E.  of  El  Toro. 
Hunter  ranch  deposit.  These  three  samples,  from  different  portions 
of  the  Hunter  ranch,  are  practically  identical  in  all  respects.  The 
material  consists  of  an  admixture  of  high-grade  china  clay  and  quartz 
sand,  in  the  proportion  of  approximately  35%  clay.  No.  63  contains 
54.4%  of  -)-  200-mesh  sand,  and  No.  64  contains  63.6%.  In  places,  a 
small  amount  of  hornblende  occurs  in  the  clay,  which  must  be  removed 
by  washing,  if  the  clay  is  to  be  used  in  whiteware  bodies.  The  most 
important  use  at  ])resent  is  in  the  manufacture  of  high-grade  fire  brick, 
at  the  plant  of  the  American  Refractories  Co.,  of  Los  Angeles,  but 
Mr.  H.  F.  Coors  has  stated  ^  that  he  believes  that  the  washed  clay  could 
be  substituted  in  any  ceramic  body  to  replace  75%  of  the  English  china 
clay  now  in  use.  The  by-product  from  washing  would  yield  a  quartz 
sand,  which,  if  hornblende  is  removed  by  tabling,  would  be  suitable  for 
glass  manufacture.  All  three  samples  were  tested  by  the  usual  methods, 
without  washing.  The  plasticity  is  weak,  the  dry  strength  low,  and 
the  dry  condition  is  coarse,  sandy,  open  and  friable.  The  colors  are 
nearly  white,  with  a  pinkish  hue  at  low  firing  temperatures,  changing 
to  yellowish  above  cone  1.  Steel  hardness  is  not  developed  within  the 
firing  range  employed.  The  fired  structure  is  coarse,  granular,  and 
w^eak.  The  total  linear  shrinkage,  at  cone  13,  is  4.0%  for  No.  63,  5.1% 
for  No.  64,  and  5.2%  for  No.  268.  The  softening  point  in  all  cases  is 
cone  33. 

No.  91  (p.  171).  Riverside  County.  Alberhill.  G.,  McB.  &  Co. 
"Main  Tunnel  Sand."  This  belongs  to  the  same  group  as  No.  13,  15, 
29,  84,  91,  96  and  229,  but  has  a  larger  proportion  of  sand  than  any  of 
the  others.  It  contains  55.0%  of  -I-  200-mesh  sand.  The  plasticity  is 
weak,  the  dry  strength  is  medium  low,  and  in  the  dried  state  it  is 
friable,  coarse-grained  and  open-textured.  The  colors  are :  dry,  V^""! ; 
wet  ll'"'\;  cones  010  to  13,  pinkish  white  at  the  lower  temperatures, 
changing  to  yellowish  w^hite  at  the  higher  temperatures.  Steel  hard- 
ness appears  at  cone  9.  The  fired  structure  is  sound,  and  coarsely 
granular.  Tlie  total  linear  shrinkage,  plastic  basis,  at  cone  13,  is  3.1%, 
which  is  a  slight  expansion  over  the  dried  condition.  The  softening 
point  is  cone  30-31.  This  material  is  used  with  more  plastic  clays  in 
firebrick  and  terra  cotta  mixes. 

No.  103  (p.  171).  Riverside  Countv.  Alberhill.  G.,  McB.  &  Co. 
''Sloan  Bone."  See  also  No.  74,  86,  87,  231,  and  232  in  class  5,  and 
No.  98  in  class  3.  This  is  a  white  bone  clay  of  exceptional  purity.  It 
contains  46.2%  of  -|-200-mesli  material.  The  plasticity  is  weak,  the 
dry  strength  is  low,  and  in  the  dried  condition  it  is  soft,  friable,  and 
open-textured.  Tlie  colors  are :  dry,  grayish  white ;  wet,  17'"f ;  cone  010, 
15"f;  cones  08  to  13,  fades  to  pinkisli  white  at  cone  1,  then  to 
yellowish  white  at  cone  13.  Finger-nail  hardness  is  present  at  cone 
010,  and  steel  hardness  at  cone  3.  All  fired  test  pieces  are  hair-cracked, 
and  one  or  two  of  them  broke  into  two  pieces.  Less  than  10%  absorp- 
tion is  obtained  at  cone  9.  The  total  linear  shrinkage,  plastic  basis,  at 
cone  15,  is  16.9%.    The  softening  point  is  cone  35. 

'  Private  communication,  July,  1925. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  261 

No.  128  (p.  54).  Amador  County.  lone.  Arroyo  Seco  Grant. 
"Shepard  Sand."  Tlii.s  is  one  of  the  'fire-sands'  for  which  the  lone 
district  is  noted.  The  material  consists  of  a  fine-nrrained  quartz-mica- 
feklspar  sand  with  sufficient  fireclay  to  render  it  -weakly  plastic.  It 
contains  48.4%  of  -|-200-mesh  sand,  and  a  lii<;li  percentage  of  the — 200- 
mesli  material  is  non-plastic.  The  dry  strength  is  low,  and  in  the  dried 
condition  it  is  very  soft.  Tlie  colors  are  nearly  white  with  a  slight 
yellowish  hue  throughout.  Finger-nail  hardness  appears  at  cone  02. 
but  steel  hardness  is  not  developed  on  firing  to  cone  15.  The  fired 
structure  is  sound,  and  fine-granular.  The  total  linear  shrinkage, 
plastic  basis,  at  cone  15  is  6.7%.  The  softening  point  is  cone  32.  The 
sand  has  important  uses  as  an  ingredient  in  fire  brick,  terra  cotta, 
pottery,  etc. 

No.  129  {\).Q2).  Amador  Count}'.  lone.  "Newman  Sand."  This  is 
almost  identical  in  its  properties  to  No.  128,  except  that  it  contains  a 
lower  percentage  of  fluxing  impurities,  and  has  a  softening  point  of 
cone  33-34.    The  percentage  of  -[-200-mesh  sand  is  55.4. 

No.  134  (p.  58).  Amador  County.  Tone  (Carbondale).  X.  Clark  & 
Sons.  "Clark  Sand."  This  is  fire-sand,  nearly  identical  in  its  prop- 
erties to  No.  128  and  129,  with  a  softening  point  of  cone  32-33.  It 
contains  55.8%  of  -(-200-mesh  sand. 

;\^o.  i55  (p.  137).  Nevada  County.  Wolf.  Coe  property.  Pine  Hill 
Mine.  See  also  No.  160.  166  (class  11),  and  167  (class  10).  This  is  a 
plastic  impure  kaolin  that  has  not  yet  been  used  commercially.  It 
contains  12.4%  of  -|-200-mesh  sand.  The  plasticity  is  fair,  thougli 
somewhat  'rubber}^'  and  Aveak.  The  dry  strength  is  medium  low, 
and  in  the  dried  condition  it  is  medium  hard,  fine-grained,  and  open- 
textured.  The  colors  are:  dry,  yellowish-white;  wet,  19"f;  cone  010, 
17"f,  decreasing  with  increasing  temperature  to  yellowish  white  at 
cone  1  and  above.  Steel  hardness  is  developed  at  cone  5.  The  fired 
structure  is  sound,  and  stony,  except  for  light  liair-cracks  at  cones  11 
and  13.  The  fired  surface  texture  is  smooth.  The  total  linear  shrink- 
age, plastic  basis,  at  cone  15  is  18.8%.  The  softening  point  is  cone  32-33. 
The  best  firing  range  is  from  cone  1  to  above  cone  13.  If  this  clay  were 
found  in  sufficient  abundance,  it  might  find  important  uses  in  the 
manufacture  of  pottery,  tile,  and  fire  brick. 

No.l60{\).l'il).  Nevada  County.  Wolf.  Coe  property.  Pine  Hill 
Mine.  See  also  No.  159,  166  (class  11),  and  167  (class  10).  This  is 
similar  to  No.  159,  but  contains  more  non-plastic  matter,  and  burns  to 
a  whiter  color.  The  plasticity  is  smooth,  but  not  strong,  the  dry 
strength  is  low,  and  in  the  dried  condition  it  is  soft-fine-grained,  and 
open-textured.  The  colors  are  :  dry,  13"'f ;  wet,  13'"d ;  cones  010  to  1, 
l'"f;  cones  3  to  9,  whiter  than  9'''f ;  cones  11  and  13.  grayish  white. 
Steel  hardness  is  not  developed  within  the  firing  range  studied,  up  to 
cone  15.  The  fired  structure  is  sound,  fine-granular,  and  smooth- 
textured.  The  maximum  total  linear  shrinkage,  plastic  basis,  at  cone 
13,  is  11.7%.  The  softening  point  is  cone  32-33.  If  it  could  be  placed 
on  the  market  cheaply,  this  clay  would  find  use  in  pottery,  tile,  and 
fire  brick  manufacture. 

No.  190  (p.  133).  Napa  County.  Calistoga.  Clark  and  Marsh 
kaolin.     This  is  a  residual  kaolin,  hand-sorted  to  remove  iron-stained 


262  DIVISION  OF  MINES  AND  MINING 

impurities.  A  larj^e  proportion  of  the  sample  consists  of  non-plastic 
kaolin  in  the  form  of  hard  jirains,  and  some  quartz  is  present.  The 
percentage  remaining  on  200-mesh  is  41.4.  The  plasticity  is  poor, 
the  dry  strength  is  medium  low,  and  in  the  dried  condition  it  is  medium 
hard,  coarse-grained,  and  open-textured.  The  colors  are  nearly  white 
throughout,  with  a  slight  pinkish  hue  in  the  raw  condition  and  when 
fired  below  cone  3,  and  a  slight  yellowish  hue  when  fired  above  cone  3. 
The  fired  structure  is  weak,  granular,  rough-textured,  and  with  a 
tendency  to  crack.  Steel  hardness  does  not  develop  within  the  firing- 
range  studied,  up  to  cone  15.  The  total  linear  shrinkage,  plastic  basis, 
at  cone  15,  is  12.0Vc.     The  softening  point  is  cone  31-32. 

Professor  Hewitt  Wilson  tested  a  sample  from  this  deposit,  and  has 
supplied  tlie  following  notes  :^  "The  fusion  was  cone  34,  indicating  a 
high  degree  of  purity,  and  a  high  degree  of  refractoriness  for  a  kaolin 
fire  brick,  sui)erior  to  that  now  on  the  market. 

"For  white  chinaware,  it  will  be  necessary-  to  use  15  to  20%  of  a 
plastic  white-burning  clay  like  a  ball  clay,  20-25%  Calistoga  clay, 
20%  feldspar,  and  35-40%  ground  (|uartz.  This  gave  (with  Washing- 
ton materials)  satisfactory  results  as  to  molding,  drying,  firing  and 
white  color." 

It  is  ajiparent  that  the  sample  tested  by  Prof.  Wilson  differed  some- 
what from  that  tested  by  the  writer. 

No.  194  {\x  221).  Sonoma  County.  Glen  Ellen.  J.  H.  Weise  prop- 
erty. This  is  a  white-burning  kaolin,  with  fair  plasticity  and  low  dry 
strength.  It  contains  34.8%  of  4-200-mesh  material.  In  the  dried  con- 
dition it  is  soft,  medium-grained,  and  open-textured.  Approximately 
25%  of  quartz  sand  is  present,  together  with  a  small  proi)ortion  of 
ferro-magnesian  mineral  grains.  The  colors  are:  dry,  ll'f ;  wet,  ll'd; 
cone  010,  9"f,  gradually  fading  to  nearly  white  at  cone  7  and  higher, 
except  for  widely  scattered  black  specks.  Steel  hardness  is  not  devel- 
oped within  the  firing  range  studied.  The  fired  structure  is  sound, 
weak,  granular,  and  open,  and  the  surface  texture  is  slightly  rough. 
The  total  linear  shrinkage,  plastic  basis,  at  cone  15,  is  6.1%.  The 
softening  point  is  cone  32.  This  clay  could  be  Avashed  free  from  quartz, 
and  used  in  the  manufacture  of  a  kaolin  fire  brick,  but  would  recjuire 
the  addition  of  a  refractory  bond  clay  in  order  to  secure  sufficient  dry 
and  fired  strength.  It  might  also  be  used  in  tile  and  porcelain  bodies, 
in  place  of  a  ]iortion  of  the  china  clay  usually  used,  if  the  ferro-mag- 
nesian minerals  were  removed  by  washing. 

No.  195  (p.  227).  Sonoma  County.  Glen  Ellen  J.  H.  Weise 
property.  This  is  a  hand-picked  sample  of  the  whitest  material  in 
the  pit  from  which  No.  194  was  taken.  It  is  more  plastic  than  No.  194, 
has  better  dry  strength,  better  fired  color,  and  higher  refractoriness. 
The  residue  on  200-mesh  is  30.2%.  Very  few  iron  specks  can  be  found. 
The  total  linear  shrinkage,  plastic  basis,  at  cone  15  is  9.9%.  The  soften- 
ing point  is  cone  33.  A  peculiarity  of  both  of  these  samples  is  that  the 
firing  shrinkage  is  greater  at  cone  9  that  at  cone  13,  but  the  shrinkage 
increases  again  at  cone  15. 

No.  208  (p.  57).  Amador  County.  Tone.  Wm.  Haverstick.  This 
is  a  sample  of  lone  sand  supplied  by  Mr.  Haverstick.     It  is  somewhat 

•  Personal  communication,  Septem.ber,  1925. 


(LAY  KESOUKCKS  AM)  CERAMR    IXDLSTUV  263 

more  jilastic  and  burns  whiter  than  other  sami)les  that  were  tested 
(see  No.  128.  12!)  and  l."U).  Tlie  total  linear  shrinka^n',  plastic  basis, 
at  cone  15,  is  8.6/<  •  The  softeninj,'  point  is  cone  32.  The  .sample  eon- 
tains  28.27o  of  +2()0-mesh  sand. 

No.  20!>  (p.  .")})).  Aiiiadoi-  County.  lone.  Sample  sii|)plie(l  by 
AVm.  Haverstick.  This  is  a  sand  containinp:  a  hi<>:her  proportion  of 
day  than  tlie  more  typical  samples  (see  No.  128,  129  and  134),  hence 
))ossessiii«>'  b(4ter  pla.sticity  and  ai-eater  shrinkap-o.  The  i-esidno  on 
2()()-mesh  is  1.1.8 /^ .  The  color  is  ^^ood,  bnt  <>'reen  scuniminji'  is  esi)e- 
cially  noticable.  Steel  hardness  is  develo])ed  at  cone  9.  The  total  linear 
shrinkage,  ])lastic  basis,  at  cone  1.")  is  lo.2%.  The  softening  point  is 
cone  32. 

No.  235  ()).  70).  Calaveras  Connty.  Valley  Springs.  Texas  Alining 
Comjtany.  This  is  a  kaolini/ed  sei-icite-talc  schist  that  has  sufficient 
jdasticity  to  permit  molding  or  pressing.  The  dry  strength  is  low,  and 
in  the  dried  condition  it  is  soft  and  friable.  The  colors  are:  dry,  17"f ; 
Avet,  15"d;  cone  06  to  1,  13"f;  cones  5  to  13,  pinkish-white.  Finger- 
nail hardness  is  developed  at  cone  1.  The  fired  strnctnre  is  sonnd, 
weak,  and  fine  granular.  The  total  linear  shrinkage,  ])lastic  basis,  at 
cone  13,  is  14.6'/f  ■  The  softening  point  is  cone  30-31.  The  material 
could  be  used  as  a  noni)lastic  ingredient  in  white  flooi-  and  wall  tile. 

No.2S6{\^.m).  Calaveras  County.  Nigger  Hill.  "Kaolin."  This 
is  an  impure  kaolin  that  has  resulted  from  the  alteration  of  a  sericite- 
talc  schist.  The  ])lasticity  is  fair,  the  dry  strength  is  low,  and  in  the 
dried  condition  it  is  soft,  friable  and  fine-grained.  The  colors  are: 
dry,  nearly  white;  wet,  grayish  w^hite ;  cones  06  to  13,  nearly  w^hite. 
Finger-nail  hardness  is  developed  at  cone  06,  and  steel  hardness  at 
cone  5.  The  fired  structure  is  sound,  medium  strong,  and  fine-granu- 
lar. The  total  linear  shrinkage,  ])lastic  basis,  at  cone  13,  is  20.9%. 
The  softening  ])oint  is  cone  29-30.  The  material  can  be  used  as  a  non- 
plastic  ingredient  in  white  tile  bodies. 

No.  237  (p.  68).  Calaveras  County.  Nigger  Hill.  Sericite-talc 
schist.  This  is  similar  to  No.  235,  but  contains  a  slightly  higher  percent- 
age of  iron.  The  total  linear  shrinkage,  plastic  basis,  is  14.5%  at  cone 
13.    The  .softening  point  is  cone  27-28. 

No.  2'>9  (\).  45).  Alameda  County.  Tesla.  This  is  a  white-buining 
fireclay  with  excellent  ])lasticity  and  medium  low  dry  strength.  It 
contains  1.6%  of  -(-200-mesh  sand.  In  the  dried  condition  it  is  soft, 
fine-grained  and  close-textured.  The  colors  are:  dry,  17'"f ;  wet,  15"f ; 
cones  010  to  04,  ])inkish  white;  cones  02  to  9,  nearly  white;  cones  11  to 
15,  yellowish  white.  Steel  hardness  is  develo])ed  at  cone  3,  and  less 
than  10%  absorption  at  cone  11.  The  fired  structure  is  stony  and 
smooth-textured.  A  few  small  cracks  appear  in  some  of  the  fired  test 
pieces.  Slight  blistering  is  noted  at  cone  13.  The  total  linear  shrinkage, 
plastic  basis,  is  20.4%  at  cone  15.  The  softening  point  is  cone  34-35. 
This  is  one  of  the  best  fireclays  tested  and  if  it  can  be  found  in  com- 
mercial quantities,  it  wall  undoubtedly  be  in  great  demand  for  fire- 
brick, whiteware,  and  tile. 

No.  268.     This  sample  has  already  been  described  (see  No.  63,  p.  260) . 


264  DIVISION  OP  MINES  AND  MINING 

2.  Medium  to  High  Strength. 

No.  15  (p.  163).  Riverside  County.  Alberhill  C.  &  C.  Co.  "Select 
Main  Tunnel."  See  also  No.  13  (class  7)  and  29.  This  clay  is  hand 
sorted  from  the  main  tunnel  fireclay  bed,  in  order  to  make  a  marketable 
grade  that  is  intermediate  in  quality  between  the  run-of-mine  material 
(No.  29)  and  the  extra-select  main  tunnel  clay  (No.  13).  It  is  used 
principally  in  the  manufacture  of  tire  brick.  It  is  fine-grained,  with 
excellent  plasticity,  medium  high  dry  strength,  and  good  dry  condition. 
It  contains  11.3%  of  plus  200-mesh  sand.  The  colors  are:  dry,  13"'f ; 
Avet.  17""b;  fired,  cream  white,  considerably  whiter  than  Ridgway's 
"f "  tone.  Finger-nail  hardness  is  developed  below  cone  010,  and  steel 
hardness  is  reached  at  cone  5.  The  total  linear  shrinkage,  plastic  basis, 
at  cone  15  is  11.7%.  The  softening  point  is  cone  30-31.  The  best  firing 
range  is  from  cone  5  to  cone  15. 

No.  28  (p.  163).  River.side  County.  Alberhill  C.  &  C.  Co.  "SII-3." 
This  is  a  clay  with  excellent  plasticity,  medium  dry  strength,  and  a  fine 
grained,  clo.se-textured  dry  condition.  It  contains  11.2%  of  -|-200- 
mesh  sand.  It  is  used  for  art  title  and  architectural  terra  cotta.  The 
colors  are:  dry,  13'"f;  wet,  13'''d;  cone  010  to  cone  1,  17"f;  cone  3 
and  above,  the  pink  gives  way  to  yellow,  and  the  tone  is  nearer  white 
than  Ridgway's  "f"  tone.  Finger-nail  hardness  is  developed  below 
cone  010,  and  steel  hardness  at  cone  7.  Vitrification  is  not  well 
advanced  at  cone  13.  The  total  linear  slirinkage,  plastic  basis,  at  cone 
13,  is  10.0%.  The  softening  point  is  cone  30.  The  best  firing  range  is 
from  cone  3  to  cone  13  or  above.  If  this  clay  were  more  plentiful,  it 
would  find  a  wide  use  in  art  title,  terra  cotta,  and  similar  products. 

No.  29  (p.  163).  Riverside  County.  Alberhill  C.  &  C.  Co.  "Main 
Tunnel."  See  also  No.  13  (class  7)  and  No.  15.  This  is  the  run-of-mine 
main  tunnel  fireclay,  and  differs  from  the  selected  varieties,  No.  13  and 
No.  15,  mainly  in  that  it  contains  more  sand  and  more  coloring  matter. 
The  percentage  remaining  on  200-mesh  is  37.2.  The  clay  is  widely  used 
in  fire  brick,  art  title,  architectural  terra  cotta,  and  for  similar  purposes. 
It  has  a  good  working  plasticity,  but  the  plastic  strength  is  low.  In 
the  dry  condition  it  is  medium  hard,  with  a  coarse,  open  texture,  and 
the  dry  strength  is  medium.  The  colors  are:  dry,  17"'f;  wet,  17"'d; 
cones  010  to  04,  13"f ;  cones  02  to  3,  13"'f ;  cones  5  to  13.  nearer  white 
than  17'"f.  Finger-nail  hardness  appears  below  cone  010,  but  steel 
hardness  does  not  develop  within  the  firing  range  of  the  tests.  The 
total  linear  shrinkage,  plastic  basis,  is  5.6%,  at  cone  15.  The  softening 
point  is  cone  30-31.  The  best  firing  range  is  from  cone  5  to  cone  15 
and  above. 

No.  44,  45  and  57  (p. 196  and  p.  194).  San  Bernardino  County.  Hart. 
No.  44  is  from  the  lower  tunnel,  and  No.  45  is  from  the  upper  tunnel  of 
the  deposit  owned  by  the  Standard  Sanitary  Manufacturing  Co.,  while 
No.  57  is  from  a  similar  deposit  in  the  same  district,  owned  by  H.  F. 
Coors.  They  are  white-burning  clays  that  may  be  classed  as  china- 
ball  clays,  as  they  possess  the  properties  of  a  mixture  of  china  and  ball 
clays  as  usually  used  in  porcelain  and  whiteware  bodies.  No.  44  con- 
tains more  quartz  than  the  other  two  samples.  It  contains  33.4% 
of  +200-mesh  material.  No.  45  contains  28.2 ^( ,  and  No.  57  contains 
21.8%.    All  three  samples  contain  a  small  proportion  of  undecomposed 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  265 

ferro-magncsiaii  minerals,  ^v}lich  is  readily  removed  in  the  usual 
processes  of  slip  preparation.  Enough  colloidal  iron  is  present  in  No. 
44  and  45  to  impart  a  yollowisli  tint  to  the  tired  clay,  hut  No.  57  is  the 
whitest  clay  that  was  tested,  and  has  a  distinctly  better  color  tlian 
English  china  clay  or  Edjrar  (Florida)  kaolin.  The  plasticity  of  all 
three  samples  is  excellent  and  the  dry  strength  is  exceptionally  high. 
Finger-nail  liardness  is  present  in  tlie  dry  state,  and  steel  hardness 
develops  at  cone  06.  Although  the  softening  point  is  cone  '-iO  for  No.  44 
and  45,  and  cone  29  for  No.  57,  bloating  begins  at  cone  11  to  13.  The 
maximum  total  linear  shrinkage,  plastic  basis,  is  9.5%  at  cones  3  to 
5  for  No.  44.  IG.O'r  at  cone  15  for  No.  45,  and  14.8%  at  cone  11  for 
No.  57.  Small  tiring  cracks  are  found  in  some  of  the  test  pieces  of  No. 
45,  fired  above  cone  3,  but  all  test  pieces  of  No.  44  and  57  are  sound. 
The  tendency  of  these  clays  to  bloat  when  used  in  porcelain  bodies  to 
be  fired  above  cone  8  is  their  most  serious  defect,  and  has  prevented 
their  continued  use  in  two  sanitary  ware  plants  that  formerly  used 
them  in  place  of  Eastern  or  English  clays.  No.  44  and  45  are  now  used 
in  the  enameling  plant  of  the  Standard  Sanitary  Manufacturing  Co., 
and  No.  57  is  used  in  the  manufacture  of  electrical  and  plumbing 
accessory  porcelain,  in  tlie  jjlant  of  the  11.  F.  Coors  Co.  The  best  firing 
range  is  from  cone  06  to  cone  8  to  11. 

No.  59.  Edgai-  kaolin  (Florida),  used  by  the  American  Encaustic 
Tiling  Comi)any.  This  is  a  white-burning  kaolin,  with  smooth  and 
strong  plasticity,  medium  dry  strength,  and  a  soft,  fine  grained, 
close-textured,  dry  condition.  Some  finely  divided  mica  is  ]-)resent, 
but  the  sample  contains  onl,y  0.6%  of  4-200-mesh  material.  A  faint 
pink  color  can  be  noted  when  fired  below  cone  1,  but  at  higher 
temperatures  the  color  closely  approximates  pure  white.  Finger-nail 
hardness  is  ohtaiiuMl  below  cone  010,  and  steel  hardness  develops  at 
cone  3.  The  fired  structure  is  stony,  and  with  the  firing  schedule  used, 
all  test  pieces  had  deep  crow-foot  cracks,  which,  however,  were  not 
continuous  enough  to  cause  disintegration.  The  total  linear  shrinkage, 
plastic  basis,  at  cone  15  is  24.8%.  The  softening  point  is  cone  34r-35. 
The  best  firing  range  is  from  cone  1  to  above  cone  15. 

-Vo.  .W  fp.  171).  Riverside  Countv.  Alberhill.  G..  McB.  &  Co.  "Main 
Tunnel  Fire  Clay."  This  should  be  compared  with  No.  13  and  229 
(class  7),  15,  29,  84  (class  6),  91  (class  1),  and  93,  post.  No.  90  con- 
tains 17.4%  of  +200-mesh  sand.  The  plasticity  is  excellent,  the  dry 
stre?igth  is  medium,  and  in  the  dri(Ml  conditiou  it  is  medium  hard,  fine 
grained  and  close-textured.  The  colors  are:  dry,  17""d;  wet,  neutral 
gray  k;  cones  010  to  13,  pinkish  white,  changing  at  the  higher  tempera- 
tures to  yellowish  white.  Finger-nail  hardness  is  developed  below  cone 
010,  and  steel  hardness  appears  at  cone  11.  Tiie  fire  structure  is  sound 
and  fine-granular.  The  total  linear  shrinkage,  plastic  basis,  at  cone 
13,  is  10.7%.     The  softening  point  is  cone  31. 

No.  93  (p.  171).  Riverside  County.  Alberhill.  C,  Mc.B.  &  Co.  "Select 
Main  Tunnel."  The  properties  of  this  clay  are  almost  identical  with 
those  of  No.  90,  except  that  it  is  finer-grained,  has  lower  porosities,  and 
the  colors  are  slightly  whiter  throughout.  The  sample  contains  1.0% 
of  4-200-mesh  sand.  Steel  hardness  is  developed  at  cone  1.  The  total 
linear  shrinkage,  plastic  basis,  at  cone  13,  is  11.8%.     The  softening 


266  DIVISION  OF  MINES  AND  MINING 

point  is  cone  80-31.     It  is  a  useful  clay  for  terra  cotta,  faience  tile, 
face  brick  and  fire  brick,  and  may  be  used  in  stoneware  and  pottery. 

No.  109  (p.  176).  Riverside  County.  Alberliill.  P.  C.  P.  Co.  "Doug- 
las ]\Iain  Tunnel."  This  is  from  an  extension  of  the  formation  from 
which  the  Alberliill  Coal  and  Clay  Company's  "Main  Tunnel"  clays 
are  mined,  see  No.  13  (class  7),  lo,  and  29,  but  is  more  closely  related 
to  the  G.,  McB.  Co.  "Main  Tunnel  Fire  Clay,"  No.  90,  in  its^  ceramic 
properties.  It  contains  22.6'/  of  -|-200-mesh  quartz  sand,  and  a  small 
proportion  of  ferro-magnesian  minerals.  Tlie  plasticity  is  very  good, 
and  the  dry  strength  is  medium  high.  In  the  dried  condition  it  is 
medium  hard,  and  has  a  medium  fine  grain  and  close  texture.  The 
colors  are:  dry,  13"f;  wet,  15"d ;  cones  010  to  1,  7"d ;  cone  3,  7"f ; 
cones  5  to  13,  Avhiter  than  17"f.  Finger-nail  hardness  appears  below 
cone  010,  and  steel  hardness  develops  at  cone  5.  The  fired  .structure  is 
sound  and  fine  granular,  with  a  slightly  rough  exterior.  The  total 
linear  shrinkage,  plastic  basis,  at  cone  13,  is  9.7%.  The  softening  point 
is  cone  30-31.  The  principal  uses  for  this  clay  are  for  fire  brick,  face 
brick  and  stoneware. 

No.  137  (p.  57).  Amador  County,  lone.  M.  J.  Bacon.  "Choc- 
olate." This  is  a  plastic  fire  clay  that  is  occasionally  marketed  as  a 
sagger  clay.  It  contains  7.0%  of  +200-mesh  sand.  The  plasticity  is 
excellent,  the  dry  .strength  is  medium,  and  in  the  dried  condition  it 
is  medium  hard,  fine-grained,  and  close-textured.  The  colors  are : 
dry,  13"f;  wet,  9"d ;  cone  010,  13"f,  fading  to  yellowish-white  at 
cone  02,  and  continuing  to  cone  13  without  appreciable  change.  Yel- 
low scumming  is  especially  noticeable.  Steel  hardness  is  developed 
at  cone  11.  The  fired  structure  is  sound,  fine-granular,  and  with  a 
slightly  roughened  surface  texture.  The  total  linear  shrinkage,  plastic 
basis,  at  cone  15  is  16.2%.    The  softening  point  is  cone  32. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


267 


TABLE    No.   12. 
I.  White-    or    Cream- Burning    Non-Calcareous    Clays. 

A.   Opt-n-buruiiig,  more  than  6'/<   appaivnt  porosity  at  cone   15. 

1.   Low  strength. 


Clay 

No. 

Vc  S.W. 

11 

8.4 

12 

10.6 

37 

16.7 

38 

5.6 

62 

7.3 

63 

5.5  + 

64 

5.7 

91 

5.5 

103 

5.0 

128 

8.9 

129 

7.7 

134 

6.8 

159 

13.3 

100 

11.5 

19  0 

19.9 

194 

14.1 

195 

14.4 

208 

9.2 

209 

12.9 

235 

6.6 

236 

13.3 

237 

6.4 

259 

15.7 

268 

6.0 

%  P.w. 

%  W.P, 

18.8 

27.2 

21.6 

32.2 

29.7 

46.4 

18.3 

23.9 

20.0 

27.3 

11.85 

17.40 

12.0 

17.7 

10.9 

16.4 

22.5 

27.5 

19.5 

28.7 

14.1 

21.8 

17.3 

24.1 

21.4 

34.7 

30.4 

41.9 

33.3 

53.2 

34.7 

48.8 

29.3 

43.7 

17.7 

26.9 

17.8 

30.7 

31.7 

38.3 

30.6 

43.9 

25.9 

32.3 

19.5 

35.2 

11.9 

17.9 

'.T.S. 

%  D.V.S. 

94 

14.5 

49 

17.8 

141 

24.4 

109 

9.6 

94 

12.2 

69 

11.0 

84 

11.2 

194 

11.0 

69 

8.0 

29 

15.2 

33 

14.2 

17- 

12.1 

135 

21.5 

84 

16.5 

171 

25.9 

95 

18.7 

188 

20.5 

+-50 

16.1 

4-90 

22.5 

Low 

9.3 

34 

19.2 

33 

9.8 

120 

26.5 

90 

11.8 

% 


D.L.S. 
4.7 
5.6 
7.5 
3.1 
3.9 
3.5 
3.5 
3.5 
2.6 
4.9 
4.4 
3.9 
6.8 
5.3 
7.9 
5.9 
6.4 
5.1 
7.1 
3.0 
6.0 
3.1 
8.1 
3.8 


Soften- 
ing pt. 
in  cone.s 
28-29 
26-27 
34 
33 
34 
33 
33 

30-31 
35 
32 

33-34 
32-33 
32-33 
32-33 
31-32 
32 
33 
32 
32 

30-31 
29-30 
27-28 
34-35 
33 


2.   Medium  to  high  strength. 


Clay 
No. 

15 

28 

29 

44 

45 

57 

59 

90 

93 
109 
137 


S.W. 

12.2 
12.1 
8.0 
18.7 
26.9 
23.3 
20.9 
13.8 
14.3 
12.9 
17.0 


%  S.W. 
%  P.W. 
%  W.P. 
D.T.S. 
%  D.V.S. 
%  D.L.S. 


%  P.W. 

13.3 
14.0 
11.8 
13.6 
15.5 
13.3 
24.0 
16.0 
16.9 
13.4 
20.6 


%  W\P. 
25.5 
26.1 
19.8 
32.3 
42.4 
36.6 
44.9 
29.8 
31.2 
26.3 
37.6 


D.T.S. 

467 

356 

242 

1375 

1562 

1744 

221 

370 

350 

437 

211 


% 


D.V.S. 
23.4 
22.7 
15.8 
34.8 
49.4 
44.4 
32.6 
24.4 
25.2 
25.0 
28.1 


D.L.S. 

7.3 

7.1 

5.1 
10.5 
14.0 
13.0 

9.9 

7.5 

7.8 

7.7 

8.5 


=  Per  cent  shrinkage  water. 

=  Per  cent  pore  water. 

=  Per  cent  water  of  plasticity. 

=  Dry  transver.se    strength,    pounds    per 

—  Drv  shrinkage,  per  cent  dry  volume. 

=  Calculated   Ihiear   drying  shrinkage,   per  cent   dry    length. 


Soften- 
ing pt. 
in  cones 
30-31 
30 

30-31 
30 
30 
29 

34-35 
31 

30-31 
30-31 
32 


square    inch,    without    sand. 


268 


DIVISION  OP  MINES  AND  MINING 


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CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


269 


Absorption  and  linear  shrinkage  curves  for  clays  of  class  1. 


ft 

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//EAT  TREATMENT  IN  CONES. 


270 


DIVISIOX  OP  MINES  AND  MINING 


Ahsoriition  and  linear  shrinkage  curves  for  clays  of  class  1. 


CIO  08  06  Of  OZ  I    3  5   7   9  II  13  IS" 


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010^08  06  Of  OZ  I    3  5    7    9  II   13  r 


NEAT  TREATMENT  IN  CONES. 


NEAT  TREATMENT  IN  CONES. 


CLAY  RESOURCES  AND  CERAMIC  IXDUSTRY 


271 


Absorption  and  limar  shrinkage  curves  for  clays  of  class  2. 
010  OB  Ob  Of  01  I    J  5    7   9// 


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HE/\T  TREATMfNT  IN  C0fiE5. 


272  DIVISION  OP  MINES  AND  MINING 

l-B.   Dense-Burning,  Less  Than  6%  Apparent  Porosity  Between  Cones  10  and  15. 

3.  Generally  Refractory,  Softening  Point  Cone  27+. 

No.  70  (p.  169).  Riverside  County.  Eniseo  Clay  Co.  "White 
Plastic."  This  is  a  white  burning,  plastic  fireclay,  similar  in  its 
general  properties  to  No.  56  (class  7),  a  German  fire  clay,  but  Avith 
lower  dry  strength,  higher  firing  shrinkage,  higher  softening  point,  and 
whiter  color.  It  contains  6.4:%  of  +200-mesh  sand.  It  has  a  strong 
and  smooth  plasticity,  medium  low  dry  strength,  and  in  the  dry  state  it 
is  soft  and  tine-grained.  The  colors  are :  dry,  13"f ;  wet,  17'"'d ;  cones 
010  to  1,  ll"f ;  above  cone  1,  nearly  white,  but  with  a  faint  yellowish 
hue.  Finger-nail  hardness  is  developed  below  cone  010,  and  steel  hard- 
ness at  cone  02.  Deep  cracks  developed  in  firing,  but  the  pieces  did  not 
shatter  sufficiently  to  fall  apart.  The  total  linear  shrinkage,  plastic 
basis,  at  cone  15  is  17.8%.  The  softening  point  is  cone  32.  The  princi- 
pal use  of  the  clay  at  present  is  in  the  manufacture  of  fire  brick,  but 
its  white  color,  fineness  of  grain,  and  excellent  plasticity  should  make 
it  desirable  for  Faience  tile  and  other  uses. 

No.  96  {\).ni).  Riverside  County.  Alberhill.  G.,  McB.  &  Co.  "No. 
10."  This  is  a  white-burning  clay  with  excellent  smooth  plasticity,  that 
is  extensively  used  in  terra  eotta  bodies.  It  contains  1.2%  of  -+-200- 
mesh  sand.  The  dry  strength  is  medium,  and  the  dried  condition  is 
medium  hard,  fine  grained,  and  close  textured.  The  colors  are :  drv, 
17""d;  wet,  17""b ;  cones  010  and  08,  13"f;  cones  06  to  13,  buff 
white.  Finger-nail  hardness  appears  below  cone  010,  and  steel  hardness 
at  cone  1.  Absorptions  under  10%  are  obtained  at  cone  9.  The  fired 
structure  is  sound  and  stony,  and  the  texture  is  smooth.  The  total  linear 
shrinkage,  plastic  basis,  is  16.0%  at  cone  15.  The  softening  point  is 
cone  32.    The  best  firing  range  is  from  cone  1  to  above  cone  13. 

No.  98  (p  171).  Riverside  Countv.  Alberhill.  G.,  McB.  &  Co. 
"Bone."  See  also  No.  74,  86,  87,  231,  and  232  in  class  5  and  No. 
103  in  class  1.  In  the  natural  state,  the  pisolitic  structure  of  this  clay 
is  not  so  well  developed  as  in  some  of  the  other  bone  clays  from  the 
district.  It  contains  30.0%  of  H-200-mesh  sand.  The  plasticity  is 
spongy  and  weak,  the  dry  strength  is  low,  and  in  the  dried  condition 
the  clay  is  soft,  friable  and  open-textured.  The  colors  are:  dry,  13"f ; 
wet,  17""b;  fired,  from  cone  010  to  cone  15,  pinkish  to  yellowish  white, 
finishing  at  a  color  that  is  whiter  than  that  of  No.  96.  Finger-nail 
hardness  appears  below  cone  010,  and  steel  hardness  is  present  at  cone 
3.  All  fired  test  pieces  are  hair  cracked.  The  surface  texture  of  the 
fired  tests  is  smooth.  The  total  linear  shrinkage,  plastic  basis,  at 
cone  15  is  18.3%.  The  softening  point  is  cone  35.  The  calcined  clay  is 
especially  valuable  as  a  fire-brick  grog. 

No.  120  (p.  53).  Amador  County.  lone.  Jones  Butte.  Arroyo 
Seco  Grant.  Leased  by  the  Stockton  Fire  Brick  Co.  "Edwin  Fire- 
clay." This  is  one  of  the  best  of  tlie  Tone  fireclays.  It  contains  30.2% 
of  -|-200-mesh  quartz-mica  sand.  The  plasticity  is  'soapy'  and  moder- 
ately strong,  the  dry  strength  is  low,  and  in  the  dried  condition  the 
clay  is  soft,  medium-grained,  and  close-textured.  Some  fine-grained 
sand  is  present.  The  colors  are :  dry,  17"f ;  wet,  17'"d ;  cones  010  to 
02,  ll"f ;  cones  1  to  5,  pinkish  white;  cones  7  to  15,  grayi.sh  white. 


CLAY  RESOtfRCES  AND  CERAMIC  INDUSTRY  ^73 

8teel  hardnoss  is  dovelopod  at  cone  '-).  Ijoss  than  10%  absorption 
appears  at  cone  D.  All  test  pieces  develop  a  network  of  hair  cracks 
on  firinfr,  bnt  do  not  disintejzrate.  The  total  linear  shrinkajje,  ]>lastic 
basis,  at  cone  1")  is  2:3.0', i.  The  softeninpr  point  is  cone  34.  The  calcined 
clay  is  nsed  as  grog,  and  the  raw  clay  as  a  i)lastic  agent,  in  the  manu- 
facture of  heavy-duty  fire  brick. 

No.  144  (p.  18o).  Sacramento  County.  Michigan  Bar.  Van  Vleck 
])roi)erty.  This  is  .similar  to  No.  143  (class  4),  but  contains  more 
impurities.  It  contains  but  0.6%  of  H-200-mesh  sand.  The  i)lasticity 
is  smofith  and  strong,  the  diy  strength  is  medium  low,  and  in  the  dried 
condition  it  is  medium  hard,  fine-grained,  and  close  textured.  The 
colors  are:  dry.  17"f ;  wet,  17"d  ;  cones  010  to  06.  13"f ;  cones  04  to  1, 
]7"f ;  cones  3  to  15  whiter  than  19"f.  Steel  hardness  is  developed  at 
cone  1.  Less  than  10' «  absorption  appears  at  cone  7.  The  fired  struc- 
ture is  sound  and  stony,  and  the  surface  texture  is  smooth.  The  total 
linear  shrinkage,  plastic  basis,  at  cone  15  is  20.6%.  The  best  firing 
range  is  from  cone  1  to  cone  15. 

No.  273  (p.  163).  Riverside  County.  Alberhill.  A.  C.  &  Co.  "SH^." 
This  clay  is  classed  by  California  consumers  as  a  ball  clay,  on  account 
of  its  smooth  and  strong  plasticity,  its  good  bonding  .strength,  nearly 
white  fired  colors,  and  good  vitrification  range  within  commercial 
firing  limits.  It  is  very  similar  to  the  Florida  kaolin  (see  No  59, 
class  2) .  The  proportion  of  +  200-mesh  sand  is  4.6% .  The  dry  strength 
is  medium,  and  in  the  dried  condition  it  is  medium  hard,  fine-grained, 
and  close  textured.  With  50%  of  — 20-mesh  to  H-30-mesh  Ottawa 
sand,  the  bonding  strength  is  70  lb.  per  sq.  in.  There  is  slight  effer- 
vescence in  hvdrochloric  acid.  The  colors  are:  dry,  9"'f;  wet,  17"'; 
cones  010  to  06,  ll"f ;  cones  04  to  5  whiter  than  ll"f ;  cones  7  to  13, 
nearly  white.  Steel  hardness  is  developed  at  cone  02,  and  less  than 
10%  absorption  at  cone  0.  The  fired  structure  is  stony  and  badly 
shattered  at  all  cone  numbers,  and  the  surface  texture  is  smooth.  The 
total  linear  shriidcage.  jdastic  basis,  at  cone  15,  is  22.4%.  The  soften- 
ing point  is  cone  34.      It  is  used  in  stoneware  and  whiteware  bodies. 

I-C.   Dense-Burning,  Less  Than  6%  Apparent  Porosity  Between  Cones  5  and  10. 

4.  Generally  Piefractory,  Softening  Point  Cone  27+. 
No.  125  (p.  53).  Amador  County,  lone  (Carbondale).  Arroyo 
Seco  Grant.  "Gage."  This  is  a  white,  fine-grained  clay,  with  a 
talcy  feel,  and  smooth,  but  weak,  plasticity.  The  dry  strength  is  low, 
and  in  the  dried  condition  it  is  soft  and  friable.  The  colors  are  dry  and 
wet,  white  with  a  greenish  hue;  cones  010  to  9,  pinkish  white;  cones  11 
and  13,  nearly  white.  The  plasticity  of  the  clay  is  not  entirely  destroyed 
until  cone  06  is  reached,  at  which  point  finger-nail  hardness  appears. 
Steel  hardness  develops  at  cone  5.  Less  than  10%  absorption  appears  at 
cone  5,  and  vitrification  is  complete  at  cone  11.  Slight  bloating  is  notice- 
able at  cone  13.  From  eone  06  to  cone  9  the  structure  is  stony,  and 
above  cone  9  it  is  glassy.  No  firing  cracks  develop.  The  maximum 
total  linear  shrinkage,  plastic  basis,  is  19.8%,  at  cone  11.  The  softening 
point  is  cone  30.  The  best  firing  range  is  from  cone  5  to  cone  11.  The 
clay  has  been  used  in  the  manufacture  of  calcimine,  and  is  suggested 
as  a  possible  ingredient  of  M'hite  tile  and  stoneware  bodies. 

18 — 54979 


274  DIVISION  OF  MINES  AND  MINING 

No.  143  (p.  185).  Sacramento  County.  Michi;iran  Bar.  Property 
of  Geo.  Cutter.  This  is  a  line-frrained,  cream-burnino:,  plastic  clay, 
quite  similar  to  No.  144  (class  ;]).  It  is  not  now  in  use,  but  was  used 
many  years  ago  as  a  stoneware  clay.  The  plasticity  is  smooth  and 
strong,  the  dry  strength  is  medium,  and  in  the  dried  condition  it  is 
medium  hard,  fine-grained  and  close-textured.  The  colors  are :  dry, 
pinkish  white;  wet,  21"'f ;  cones  010  to  1,  pinkish  white;  cones  3  to  7, 
19''f;  cones  9  to  13,  21"'f.  Steel  hardness  is  developed  at  cone  1. 
The  fired  structure  is  sound,  and  stony,  and  the  surface  texture  is 
smooth.  Less  than  10%  absorption  is  obtained  at  cone  5.  The  maxi- 
mum total  linear  shrinkage,  plastic  basis,  at  cone  11,  is  23.2%.  The 
softening  point  is  cone  32.  When  used  alone,  the  clay  warps  seriously 
both  during  drying  and  firing,  but  will  stand  much  abuse  without 
cracking.     The  best  firing  range  is  from  cone  1  to  cone  11. 

No.  240  (p.  52).  Amador  County,  lone.  Core  drill  sample.  Ea.st 
side  of  Lot  237,  Arroyo  Seco  Grant.  This  is  a  cream-burning  clay. 
The  dry  strength  is  medium,  and  in  the  dried  condition  it  is  soft, 
friable,  fine-grained,  and  close-textured.  The  colors  are :  dry,  15"f ; 
wet,  l'"f ;  cones  010  to  02,  13"f ;  cones  1  to  7,  21'"f;  cones  9  to  13, 
23''"'f.  Steel  hardness  is  developed  at  cone  02,  and  less  than  10% 
absorption  at  cone  1.  The  fired  structure  is  stony,  and  one  or  two 
small  cracks  are  present  in  each  fired  test  piece.  The  surface  texture 
is  smooth.  The  maximum  total  linear  shrinkage,  plastic  basis,  at  cone 
13,  is  23.6%.  The  softening  point  is  cone  32-33.  The  long  vitrifica- 
tion range  is  especially  to  be  noted.  The  possible  uses  are  as  a  refrac- 
tory bond  clay  in  fire  brick,  terra  cotta,  faience  tile,  and  stoneware. 
It  is  the  equivalent  of  the  well-known  Dosch  chiy,  Xo.  136  (class  8), 
and  has  a  slightlv  better  color. 


TABLE    No.   14. 

I.  White-    or    Cream-Burning    Non-Calcareous    Clays. 

B.   Dense-burning,  less  than  6%  apparent  porosity  between  cones  10  and  15. 

3.   Generally  refractory,   softening  point  cone   274-- 


Soften- 

Clay 

ing  pt. 

No. 

%  s.w. 

%  P.W. 

%  W.P 

D.T.S. 

%  D.V.S. 

% 

D.L.S. 

in  cones 

70 

12.8 

18.7 

31.5 

171 

21.9 

6.9 

32 

96 

13.7 

15.9 

29.6 

398 

25.0 

1 . 1 

32 

98 

6.5 

20.9 

27.4 

81 

10.8 

3.4 

35 

120 

6.8 

29.6 

36.4 

93 

9.9 

3.1 

34 

144 

17.7 

22.1 

39.8 

165 

29.4 

8.9 

31 

273 

15.6 

21.9 

37.5 

249* 

25.7 

7.9 

34 

*  Bonding    s 

trength,    with 

50%    of 

Ottawa    sand 

(  —20- 

,-1-  30-mesh) 

is    70    lb. 

per  sq. 

in. 

C.   Dense-burning,  less  than  6%  apparent  porosity  between  cones  5  and  10. 
4.   Generally  refractory,   softening  point  cone   274-. 


Glay 
No.          %  S.W.           %  P.W.            %  W.P. 

D.T.S. 

% 

D.V.S. 

%  D.L.S. 

Soften- 
ing pt. 
in  cones 

125                11.7                  31.1                     42.8 
143                22.5                 21.7                   44.2 
240                20.6                  22.3                    42.9 

26 
245 
335 

ity. 

pounds   i)ei 
nt    dry    vol 

shrinkage, 

16.5 
36.8 
33.7 

•   square    inch, 
unie. 
per   cent    dry 

5.3 
11.0 
10.2 

without 
length. 

30 
32 
32-33 

%  S.W.      =:  Per  cent  shrinkage  water 
%  P.W.      =  Per  cent  pore  water. 
%  W.P.      =  Per  cent  water  of  plastici 
D.T.S.         =  Dry    transverse    strength, 
%  D.V.S.   =:  Drying   shrinkage,    per   ce 
%  D.L.S.    =  Calculated    linear    drying 

sand. 

CLAY  RESOURCES  AND  CERATSIIC  INDUSTRY 


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CLAY  KESOUKCKS  AND  CEKAMIC  INDUSTRY  277 

II.   BUFF-BURNING    CLAYS. 
A.    Refractory   Clays,  Softening   Point  Cone  27  4 

a    Oi'EN-BrHNixc.  Mori:  Than  6'/<    Aitahknt   Pohositv  at  Cone  15. 

5.  Low  Strength. 

Xo.  17  (p.  168).  Riverside  County.  Alberliill  C.  &  C.  Co.  "Bone." 
A  medinm-grained  bone  clay,  witli  a  deeid(>d,  bnt  not  well-developed 
pisolitic  .structure  in  tlie  eruile  state.  It  is  used  in  the  manufacture  of 
fire  brick,  high-temperature  cement,  and  to  some  extent  in  saggers. 
It  contains  29.0 ';f  of  +  200-mesh  grains,  has  short  plasticity,  and  dries 
rapidlv  to  a  soft,  rough  textured  condition,  witli  medium  low  dry 
strength.  The  colors  are:  dry,  l;}""d;  wet,  l;i""i;  cones  010  to  06, 
17''f ;  cone  04,  17'''f ;  cones  02  to  5,  whiter  than  17'"f ;  cones  7  to  13, 
17'"f.  All  test  pieces  fired  above  cone  02  were  'crow-footed.'  Finger- 
nail hardness  is  developed  below  cone  010,  and  knife  hardness  appears 
at  cone  5.  The  total  linear  shrinkage,  plastic  basis,  is  18.5%  at  cone  15. 
The  softening  point  is  cone  34.  The  best  firing  range  is  above  cone  5. 
The  principal  value  of  this  clay  is  to  increase  the  refractoriness  of  fire 
brick  bodies. 

No.  23  (p.  163).  Riverside  County.  Alberliill  C.  &  C.  Co.  "West 
Blue."  This  is  one  of  the  more  important  Alberhill  clays,  and  is  widely 
used  for  light-pink  and  butf  face  brick,  for  sewer  pipe,  and  in  fire  brick 
to  decrease  porosity.  It  contains  11.0%  of  +  200-mesh  sand.  The 
plasticity  is  excellent  and  the  dry  strength  is  medium  low.  In  the  dry 
condition  the  clav  has  a  medium  hardness,  a  fine  grain  and  a  close 
texture.  The  colors  are:  dry,  17""f ;  wet,  21""  ;  cones  010  to  04,  5'f ; 
cone  02,  ll"f ;  cones  1  and  3,  13"f ;  cones  5  to  9,  ]7"f ;  cone  11,  17"d ; 
cones  13  and  15,  15"b,  with  prominent  iron  specking.  Finger-nail 
hardness  is  developed  at  cone  08,  and  steel  hardness  at  cone  3.  The 
maximum  total  linear  firing  shrinkage,  plastic  basis,  at  cone  13,  is 
13.7%.  Slight  bloating  is  apparent  at  cone  15.  The  softening  point 
is  cone  29.  The  best  firing  range  is  from  cone  1  to  cone  13.  A  pleasing 
mottled  texture  can  be  produced  by  flashing. 

No.  66  {\).\ld).  Riverside  County.  Corona.  McKnight  pit.  Pacific 
Clay  Products  Co.  "Red  IMcKnight."  This  is  a  bull'-burning  clay 
containing  a  large  proportion  of  non-plastic  material.  It  is  suitable 
for  face  brick  manufacture,  and  as  an  ingredient  of  sewer  pipe  mixes. 
The  plasticity  is  good,  though  weakened  by  the  presence  of  54.4%  of 
+  200-me.sh  sand.  The  dry  strength  is  medium  low,  and  the  dry  con- 
dition is  coarse,  open,  soft  and  friable.  The  colors  are :  dry,  9" ;  wet, 
9"i;  cones  010  to  02,  9'b;  cone  1,  9'd  ;  cone  2,  ll'd;  cone  5,  9'f ;  cones 
7  and  9,  9"d;  cones  11  and  13,  15"d.  Fing<>r-nail  hardness  develops 
beloAV  cone  010,  and  steel  liardness  at  cone  7.  The  fired  condition  is 
sound,  open,  granular,  and  medium  strong.  The  total  linear  shrinkage, 
plastic  basis,  at  cone  13,  is  5.6%.  The  softening  point  is  cone  28.  The 
best  firing  range  is  above  cone  5. 

No.  67  (p.  179).  Kivt'i-si<h'  Count  \-.  Corona.  IMcKniglit  pit.  Pacific 
Clay  Products  Co.  "McKniglit  Fire  Clay."  This  is  a  sandy  fire  clay 
with  fair  plasticity,  medium  low  dry  strength,  and  a  granular,  friable, 
dry  condition.  It  contains  64.2%  of  -)-  200-mesh  sand.  The  colors  are : 
dry,  13""d:  wet,  13""i;  cones  010  to  7,  17"f;  cones  9  to  13,  nearly 


r: 


278  DIVISION  OF  MINES  AND  MINING 

17"'f'.  Steel  hardness  is  not  developed  within  the  firing  range  studied, 
up  to  cone  15.  The  fired  structure  and  texture  is  weak,  coarse-grained, 
and  friable.  The  total  linear  shrinkage,  plastic  basis,  at  cone  15  is 
7.2%.  The  soften in<i'  ])oint  is  cone  3.'1.  For  best  results  in  firebrick 
manufacture,  tliis  ehiy  should  Ix*  mixed  with  a  more  ])lastic  fire  clay. 

A^o.  77  (p.  !()!)).  ItiversideCounl.v.  Emsco  Clay  Co.  "Pink  Mottled." 
This  is  a  buff-burning  plastic  fire  clay  that  is  especially  valuable  as  a 
face-brick  clay.  The  plasticity  is  smooth  and  strong,  without  sticki- 
ness, the  dry  strength  is  medium  low,  and  in  the  dried  state  it  is  soft, 
fine-grained  and  open-textured.  The  sample  contains  11.0%  of  -f-200- 
mesh  sand.  The  colors  are:  dry,  7'M;  wet,  7";  cones  010  and  08,  5'f ; 
cone  06,  9"f;  cone  04,  7"f ;  cone  02,  i;r'f ;  cone  1,  15"f ;  cones  8  and  5, 
17"f ;  cones  7  to  1,  17'"f ;  and  cone  ]:?,  17"d.  A  good  range  of  pinks, 
hutl's,  and  creams  is  covered,  '^fhe  fired  exteriors,  especially  above  cone 
5,  are  lightly  mottled  wi1h  iron  specks.  F'inger-nail  hardness  is 
developed  at  cone  010,  and  steel  hardness  at  cone  5.  The  fired  structure 
is  sound,  stony  and  strong.  The  total  linear  shrinkage,  plastic  basis, 
at  cone  13,  is  13.1%.  The  softening  point  is  cone  30-31.  The  best 
firing  range  is  from  cone  04  to  above  cone  13. 

No.  7i  (p.  174).  Riverside  Countv.  Alberhill.  Los  Angeles  Brick  Co. 
"Bone."  See  also  No.  86,  87,  231  and  232  in  the  same  class,  No.  98  in 
class  3,  and  No.  103  in  class  1.  In  the  imtural  state,  this  clay  has  a 
well  developed  pisolitic  structure,  and  is  hard  and  brittle.  It  is  used 
in  the  manufacture  of  high-grade  fii'e  brick.  The  sample  contains 
47.6%  of  -)-200-mesh  sand.  The  plasticity  is  spongy  and  weak,  the 
dry  strength  is  low,  and  the  dried  condition  is  soft,  friable,  and  open- 
textured.  The  colors  are:  dry,  ll'd;  wet,  ll'i;  cones  010  and  08,  7'd ; 
cones  06  and  04,  5'f;  cones  1  to  5,  9'f;  cones  7  to  11,  15'f ;  cone  13, 
13'd.  Finger-nail  hai'dness  is  developed  at  cone  08  and  steel  hardness 
appears  at  cone  1.  All  fired  test  pieces  have  deep  hair  cracks,  but  do 
not  disintegrate.  The  total  linear  shrinkage,  plastic  basis,  at  cone  15 
is  24.6 /^,  most  of  which  takes  place  during  firing.  The  softening  point 
is  cone  33-34.  The  clay  is  especially  valuable  as  a  grog  in  fire  brick 
mixtures  after  calcination  at  cone  11  to  15. 

No.77  {\^.^1A).  Riverside  (V)unty.  Alberhill.  L.  A.  B.  Co.  "Gray 
No.  20."  This  clay  is  very  similar  to  No.  76  (class  6),  but  contains 
more  silica,  is  finer-grained,  and  has  a  stronger  fired  structure.  It  is 
used  in  face  brick  and  fire  brick.  It  contains  6.6%  of  -(-200-mesh  sand. 
The  ])histicity  is  excellent,  the  di-y  strength  is  medium  low,  and  the 
dried  condition  is  medium  hard,  fine-grained,  and  close-textured.  The 
colors  are:  dry,  17"'f ;  wet,  13'"f ;  cone  010  to  04,  13"f ;  cones  02  to  13, 
17"'f,  or  sliglitly  whiter.  Steel  hardness  api)ears  at  cone  1.  All  fired 
structures  ai'e  sound,  and  above  cone  1  are  stony.  Al)sori)tion  below 
10%  is  obtained  at  cone  7.  The  maximum  total  linear  shrinkage, 
l)lastic  basis,  at  cone  13,  is  16.3%.  Bloating  begins  above  cone  13.  The 
softening  point  is  coiic  30-31.  Tlic  best  (iring  range  is  fi-om  cone  1  to 
above  cone  13. 

A'o.  ;.'Mp.  174).  {{ivei'side  ("ounty.  Alberhill.  L.  A.  B.  Co.  "Fire- 
clay." This  is  a  buiV-burning,  sandy  fireclay  witJi  low  ])lastic  strength, 
and  medium  loAv  dry  strength.  It  contains  48.4%  of  -f-200-mesh  sand. 
In  the  dried  condition  it  is  friable,  coar.se-grained  and  open-textured. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  279 

The  colors  arc:  dry,  17"f ;  wet,  18""b;  cones  010  to  04,  9"f ;  cone  02, 
ll"f ;  cone  1,  13"f ;  cone  8.  17"f ;  cones  5  to  15,  17'"f.  Very  few  black 
specks  appear  on  firing;.  Fin<i:er-nail  hardness  appears  below  cone  010, 
but  steel  hardness  is  not  reaclied  below  cone  15.  The  fired  structure  is 
sound,  coarse-grained,  and  open-textured.  Tlie  total  linear  slirinkafje, 
plastic  basis,  at  cone  15  is  5.4 /v,  nio.st  of  whicli  takes  place  during 
drying.  Tlie  softening  point  is  cone  )51-;^2.  The  best  firing  range  is 
above  cone  9. 

No.  86  (p.  174).  Kivcrsi.h'  Couuly.  Alberhill.  L.  A.  15.  Co.  "No. 
26  Bone."  8ee  also  No.  74,  87,  2;n  and  232,  to  which  this  clay  is  closely 
related.  The  plasticity  is  spongy  and  weak,  the  dry  strengtli  is  low, 
and  the  dried  condition  is  soft,  friable,  and  open-textured.  The  sample 
contains  57.8'^y  of  +20()-niesli  material.  The  colors  are:  dry,  17"'d; 
wet,  19";  cones  010  to  5,  9'd ;  cones  7  to  11,  15'f;  cone  13,  17"d. 
Finger-nail  hardness  is  developed  at  cone  08,  and  steel  hardness  appears 
at  coiie  1.  Test  pieces  have  hair  cracks,  when  fired  above  cone  1,  but 
do  not  disintegrate.  Tiie  total  linear  shrinkage,  plastic  basis,  at  cone 
13,  is  12.3%.    The  softening  point  is  cone  33-34. 

No.  87  (}).  174).  Riverside  County.  Alberhill.  L.  A.  B.  Co.  "White 
Bone."  See  also  No.  74,  86,  231  and  232.  This  variety  is  now  design- 
nated  "Smooth  Bone."  and  is  closely  similar  to  sample  No.  232.  It 
contains  31.0%  of  -|-200-mesh  material.  The  plasticity  is  better  than 
that  of  No.  86,  the  dry  strength  is  low,  and  tlie  dried  condition  is  soft, 
friable  and  open.  Tlie  colors  are:  dry,  17"f ;  wet,  17'"f ;  cones  010  to 
06,  7'f ;  cones  04  to  13,  jniikish  and  yellowish  white.  Finger-nail  hard- 
ness is  developed  at  cone  08,  and  steel  hardness  at  cone  3.  All  fired  test 
pieces  are  lightly  hair-cracked.  Less  than  10%  absorption  is  obtained 
at  cone  11.  The  total  linear  shrinkage,  plastic  basis,  at  cone  15  is 
18.3%.     Tlie  softening  point  is  cone  34. 

No.  104  (p.  171).  Riverside  County.  Alberhill.  G.,  McB.  &  Co. 
"No.  5  Sloan."  This  is  a  plastic  fireclay,  high  in  alumina.  The  dry 
strengtli  is  medium  low,  and  the  dried  condition  is  soft,  medium- 
grained,  and  open-textured.  It  contains  32.2%  of  -f200-mesh  sand. 
The  colors  are:  dry,  17"f;  wet,  13"d ;  cones  010  to  02,  7"b ;  cone  1, 
ll"f ;  cones  3  to  9,  17''f ;  cones  11  and  13,  13'"'f.  Numerous  small  iron 
specks  are  visible  when  fired  to  cone  11  or  above.  Finger-nail  hardness 
appears  below  cone  010  and  steel  hardness  at  cone  1.  All  fired  test 
pieces  are  lightly  hair  cracked,  and  those  that  were  fired  at  the  higher 
temperatures  fell  apart  into  Iwo  or  more  pieces.  The  surface  texture 
of  the  fired  i)ieces  is  smooth.  Less  than  10%  absorption  is  obtained  at 
cone  5.  The  maximum  total  linear  shrinkage,  plastic  basis,  at  cone  13, 
is  23.6 /<  .    The  softening  point  is  cone  34-35. 

No.  126  (p.  52).  Amador  County.  lone.  Arroj'o  Seco  Grant. 
"Baker."  This  is  a  ]ilastic  fireclay  containing  19.6%  of  -|-200-mesh 
(|uartz  and  undecomposcd  feldspar  grains.  The  plasticity  is  good,  the 
diy  strengtli  is  low.  and  in  the  dried  condition  it  is  soft,  friable  and 
mediuiu-grainetl.  Tlie  colors  are:  dry,  17"'f ;  wet,  17'"d ;  cones  010  to 
9,  17"f ;  cones  11  and  13,  17"'f.  Steel  hardness  does  not  appear  within 
the  firing  range  studied  (cones  010  to  15).  Less  than  10/^  absorption 
appears  at  cone  11.     All  fired  test  pieces  are  hair-cracked.     The  total 


2H0  DIVISION  OF  MINES  AND  MINING 

linear  shrinkage,  plastic  l)asis,   at   cone  15  is  19.5%.     The  softening 
point  is  cone  33-34.    The  best  firing  range  is  above  cone  9. 

No.  138  (p.  57).  Amador  County,  lone.  :\r.  .1.  IJacon.  "Bacon 
Bottom."  This  clay  has  a  smooth  plasticity,  medium-low  dry  strength, 
and  in  the  dried  ccnidition  it  is  soft,  fine-grained  and  open-textured. 
It  contains  4.2''/^  of  -f200-mesh  sand.  The  colors  are:  di'v,  13"f ;  wet, 
]7"f;  cone  010,  17"f;  fading  to  ])iiddsh  white  at  cone  02,  and  to 
yelloAvish  Avhite  at  cone  5;  cones  11  to  15,  19"d.  Scattered  iron  specks 
are  noticeable  at  cones  11  to  15.  Finger-nail  liardness  is  ap])roximated 
at  eone  OlU,  antl  steel  hardness  is  reached  at  cone  11.  The  tiretl  struc- 
ture is  sound  and  fine-granular,  and  the  fired  surface  is  slightly  rough. 
The  total  linear  shrinkage,  i)lastic  basis,  at  cone  15  is  18.1%.  The 
softening  point  is  cone  29-30.  The  clay  may  be  used  in  sanitary 
porcelain  bodies  to  rejilace  ])art  of  the  flint  and  china  clay  ordinarily 
used. 

No.  liO  ({).  56).  Amado]-  County.  lone.  Arroyo  Seco  Grant, 
lone  Fire  Brick  Co.  "Sand."  This  is  a  fire-sand,  nearly  identical  in 
its  properties  to  No.  128  (class  1)  with  a  softening  point  of  cone  32. 
Tt  contains  \b.()'/v  of  +200-mesh  sand.  The  fired  colors  are:  cones 
010  to  04,  7"b;  cone  02,  7"d;  cone  1  to  7,  17"  d;  cones  9  and  11, 
]9"d;  cone  13,  19"f. 

No.  141  (p.  58).  Amador  County.  Jackson  Valley.  lone.  Leased  to 
W.  S.  Dickey  Clay  IManufacturing  Co.  This  is  a  high-grade  plastic 
fireclay,  yet  it  contains  38.8%  of  -j--00-mesh  matei'ial.  The  plasticity 
is  fair,  the  dry  strength  is  low,  and  in  the  dried  condition  it  is  soft, 
medium-grained  and  open-textured.  The  colors  are:  dry  l"'"f; 
wet,  light  gull  gray  (9)f ;  cones  010  to  06,  7"f ;  cone  04,  17''f.  With 
increasing  temperature,  yellow  replaces  pink,  and  at  cones  11  and  13, 
the  color  approximates  19"f.  Steel  hardness  is  not  developed  within 
the  range  of  temperatures  studied  (up  to  cone  15).  The  fired  struc- 
ture is  granular,  ami  hair-ci-acked,  and  the  texture  is  slightly  I'ough. 
The  total  linear  shrinkage,  plastic  basis,  at  cone  15,  is  14.1/1.  The 
softening  point  is  cone  34.  This  is  one  of  tlie  best,  fireclays  in  the 
state,  and  brick  made  from  this  clay,  with  a  calcined  grog  of  the 
same  material,  are  exceptionally  good. 

No.  142  (p.  58).  Amador  County.  Jackson  Valley,  lone.  Leased 
to  W.  S.  Dickey  Clay  Manufacturing  Com])any.  This  is  similar  to  No. 
141,  but  contains  more  eolnring  and  Huxing  impurities.  There  is  35.8% 
of  +200-mesh  sand.  The  drv  strength  is  medium  low.  The  colors  are: 
dry,  17"f;  wet,  15"d;  cones  010  to  OH.  7"b;  cones  04  and  02,  7"d  ; 
cone  1,  7"f;  cone  3,  9"f ;  cone  5,  9'"f ;  cone  7,  17'"f;  cones  9  to  13, 
]7"d.  Steel  hardness  is  developed  at  cone  3.  The  fired  structure  is 
coarse-granidar,  and  lightly  hair-eracketl,  with  a  roughened  surface 
texture.  The  total  linear  shrinkage,  i)lastic  basis,  at  cone  13  is  14.7%. 
The  softening  point  is  cone  32-33.  Except  for  lower  refractoriness, 
this  clay  is  more  workable  than  No.  141,  on  account  of  greatei"  strength 
and  less  fire-cracking. 

No.  191  (p.  133).  Najia  County  Calistoua.  Clark  and  Marsh. 
Average  sample.  This  is  similar  to  No.  190  (class  1),  but  contains  more 
ii*on,  and  has  even  less  plasticity  and  fired  strength.     The  colors  are : 


CLAY  RESOURCES  AND  CERAMIC   INDLSTRV  281 

dry,  17'cl ;  wet,  ll'b ;  cones  010  and  08,  9'b ;  eone  06,  9'd ;  cones  04  to  5, 
7'd;  cone  7,  9'f;  cones  1)  to  13,  17"'f.  The  total  linear  shrinkaue, 
plastic  basis,  at  cone  1:5,  is  8.1%.     The  sot'teninj^-  point  is  cone  30-31. 

Xo.  192  (p.  133).  Xapa  County.  Calisto^'a.  Tninicl  \w\o\\  Clark 
and  ]\rarsh  property.  This  .sample  contains  a  much  higher  proportion 
of  i>lastic  matter  than  No.  190  or  191,  but  at  the  same  time  contains 
sufficient  iron  to  iiivc  pale  ImlV  lii'fd  colors.  The  residue  on  200-mesh  is 
26.2^;.  The  i)lasticity  is  fail',  the  dry  stren«>th  is  medium  low.  and 
in  the  dried  condition  it  is  inediuiii-hard,  fine-jirained,  and  open-tex- 
tured. The  eoloi-s  are:  dry.  pinkish  white,  wet,  17"f ;  cone  010,  13"f  : 
fadin<i-  to  ])iidvisli  white  at  cone  3,  then  chanf^ino-  to  17"'f  at  cones  11 
to  lo.  Steel  harilne.ss  is  not  develoiied  within  the  fii'in<i'  ranji'e  studied, 
up  to  cone  15.  The  fired  structure  is  medium-stron<i',  tine-granular, 
and  at  high  tiring  temperatures  is  .slightly  hair-cracked.  The  .surface 
texture  is  slightly  i-oughened.  A  few  iron  s])ecks  are  present.  The 
total  linear  shrinkage,  i)lastic  basis,  at  cone  15  is  17.1%.  The  soften- 
ing point  is  cone  31. 

No.  231  (p.  174).  Riverside  County.  Alberhill.  L.  A.  B.  Co.  "High 
Alumina  Bone."  See  also  Xo.  74,  86,  87,  and  232.  In  the  natural 
state  this  cI-ay  has  a  well-developed  pisolitic  structure.  The  plasticity 
is  spongy  and  weak,  the  dry  strength  is  low,  and  in  the  dried  con- 
dition it  is  soft,  coarse,  and  open.  The  colors  are  :  dry,  9"d  ;  wet,  ll"b ; 
cones  010  and  08,  9'd;  cones  06  to  02,  9"f;  cones  1  to  5,  17"f;  cones 
7  to  13,  19"f.  Finger-nail  hardness  is  developed  at  cone  1,  but  .steel 
hardness  is  not  iiresent  at  cone  15.  The  fired  structure  is  crumbly 
and  weak  at  low  firing  temperatures,  and  hair-cracked  at  higher 
temperatures.  The  total  linear  shrinkage,  ])lastic  basis,  at  cone  15, 
is  19.6%.     The  softening  i)oint  is  cone  34-35. 

No.  232  (p.  174).  Riverside  County.  Alberhill.  L.  A.  B.  Co. 
"Smooth  Bone."  See  es])ecially  No.  87,  to  which  this  sample  is  closely 
siiidlar,  except  that  it  is  more  i)lastic,  and  less  than  M)'/(  absorj)tion  is 
obtained  at  a  lowei-  firing  tem]ierature,  cone  9,  instead  of  at  cone  11. 
The  total  linear  shrinkage,  ])lastic  basis,  at  cone  15  is  20.6%.  The  soft- 
ening point  is  cone  34-35. 

No.  239  (p.  52).  Amador  County.  lone.  Core  drill  sample.  Lot 
254.  Arroyo  Seco  ({rant.  A  sandy  clay  with  fair  plasticity  and  low 
dry  strength.  It  contains  58.0%  of  +200-mesh  sand.  In  the  dried 
condition  it  is  soft,  fine-grained,  and  open-textured.  The  colors  are: 
dry,  l""f ;  wet,  15"'"b ;  cones  1  and  5,  9"'f;  coues  9  and  13,  17'"d. 
Steel  hardness  is  not  develo|)ed  at  cone  13.  The  fired  .structure  is 
sound  and  fine-granular.  The  total  linear  shrinkage,  plastic  basis,  at 
cone  13,  is  3.1%.  The  softening  point  is  cone  31.  The  material  could 
be  mixed  with  a  more  pla.stic  clay  for  the  manufacture  of  firebrick. 

No.  244  (p.  52).  Amador  Connty.  lone.  Core  di-ill  hole  No.  54, 
Arroyo  Seco  Grant.  This  is  siniihn-  to  No.  240  (class  4),  but  contains 
a  larger  proportion  of  fine  sand  and  ferro-magnesian  minei'als.  The 
plasticity  is  good,  l)ut  willi  a  tendency  to  stickiness.  The  dry  strength 
is  medium  low,  and  in  the  dried  condition  it  is  soft,  fine-grained,  and 
open-textured.  The  colors  are:  dry,  pinkish  white;  wet,  l"'"f;  cone 
1,  19"f ;  cones  5  and  9,  17"d ;  cone  13,  17""d.    Steel  hardness  is  present 


» 


282  DIVISION  OP  MINES  AND  MINING 

at  cone  1,  and  less  than  10%  absorption  appears  at  cone  5.  Blistering 
was  noted  at  cone  13,  althougli  the  softening  point  is  cone  31-32.  The 
fired  structure  is  stony,  and  sound,  except  for  a  few  small  cracks  at 
cone  13.  The  surface  texture  is  suiootli.  The  maximum  total  linear 
shrinkage,  plastic  basis,  is  20.8%,  at  cone  9.  It  could  be  used  in  terra 
cotta  and  faience  tile  bodies. 

No.  250  (p.  52).  Amador  County.  lone.  Core  drill  No.  56-3, 
Arroyo  Seco  Grant.  This  sample  contains  but  1.4'/  of  -|-2()0-mesh 
sand.  The  plasticity  is  good,  without  stickiness,  tlie  dry  strength  is 
medium-low,  and  in  the  dried  condition  it  is  soft,  fine-grained,  and 
open-textured.  The  color.s  are:  dry,  grayish  white;  wet,  carbon  gray; 
cone  1,  nearly  white;  cones  5  and  9,  19"f ;  cone  13,  IT'^d.  Steel  hard- 
ness and  less  than  10%)  absorption  are  developed  between  cone  1  and 
cone  5.  In  the  fired  condition  the  non-plastic  grains  are  well  cemented 
in  a  groundmass  of  clay.  Numerous  fine,  but  deep,  cracks  appear  in 
the  fired  test  pieces.  The  surface  texture  is  moderately  rough.  The 
total  linear  shrinkage,  plastic  basis,  at  cone  13,  is  14.7%.  The  softening 
point  is  cone  31.  It  is  a  suitable  material  for  terra  cotta,  tile,  and 
fire  brick  bodies. 

No.  270  (p.  140).  American  Refractories  Co.  "Arc  Fire  Clay."  This 
is  a  sample  of  fireclay  from  which  the  "Arc"  brand  of  fire  brick  is 
manufactured.  There  is  slight  effervescence  in  hydrochloric  acid.  The 
plasticity  is  excellent,  the  dry  strength  is  medium  low,  and  in  the 
dried  condition  it  is  soft,  medium-grained,  and  open-textured.  It 
contains  32.0%  of  -|-200-mesh  sand.  The  colors  are:  dry,  13"'d;  wet, 
13"'b;  cones  010  to  06,  9"f;  cones  04  and  02,  15"f;  cones  1  to  7, 
yellowish  white;  cones  9  to  13,  19"'f.  The  surface  is  slightly  mottled 
with  iron  specks  above  cone  9.  Steel  hardness  is  developed  at  cone  11. 
The  fired  structure  is  sound,  and  granular,  and  the  surface  texture  is 
rough.  The  total  linear  shrinkage,  plastic  basis,  at  cone  13,  is  12.8%. 
The  softening  point  is  cone  32. 

No.  282  (p.  141).  Orange  Countv.  Santa  Ana  Canvon.  Goat  Ranch. 
G.,  McB.  &  Co.  "Flint  Fire  Clay."  This  sample  "was  prepared  by 
wet  pebble-mill  grinding  through  200-mesh,  followed  by  seven  days' 
ageing  in  the  plastic  state,  with  frequent  pugging.  This  produced 
good  plasticity.  The  dry  strength  is  medium  low,  and  in  the  dried 
condition  it  is  medium  hard,  fine-grained,  and  close-textured.  The 
colors  are:  dry,  17""f ;  wet,  21""d;  cones  010  to  04,  13"f ;  cones  02 
to  9,  nearly  white;  cones  11  and  13,  17"d.  Steel  hardness  is  developed 
at  cone  5  and  less  than  10%)  absorption  at  cone  13.  The  fired  structure 
is  fine-granular,  and  the  surface  texture  is  smooth.  All  test  pieces  are 
shattered,  but  most  of  them  remain  in  one  piece.  The  total  linear 
shrinkage,  plastic  basis,  at  cone  15  is  18.0%.  The  softening  point  is 
cone  33. 

No.  285  (p.  232).  Tulare  County.  Ducor.  W.  A.  Sears  deposit.  See 
also  No.  283-A  and  B,  class  9,  and  284,  class  10.  This  is  the.  most  satis- 
factory of  the  clays  that  were  tested  from  this  ])roperty.  The  material 
is  an  impure  kaolin,  has  fair  plasticity,  and  medium-low  diy  strength. 
In  the  dry  condition  it  is  nu^lium  hard,  fine-grained,  and  open-texturetl. 
The  colors  are :  dry,  cream  white ;  wet,  15  b;  cones  010  to  1)6,  9"f ;  cones 
04  to  5,  17"d;  cones  7  and  9,  15"d;  cones  11  av^  13,  13"d;  cone  15, 


CLAY  RESOUKC'ES  AND  CEKAAIIC  INDUSTKY 


288 


15"d.  These  are  suitable  buffs  for  face  brick,  but  tlie  surface  is  badly 
contaminated  with  yellow  stainin-ir.  Tlici-e  is  no  evidence  of  vitrifica- 
tion up  to  cone  15,  the  ui)i)ei-  limit  studied.  The  fired  structure  is 
sound,  fine-g:rained,  and  open-textured,  without  irreat  strength.  The 
total  linear  shrinkage,  plastic  basis,  at  cone  15,  is  10.8%.  The  softening 
point  is  cone  80-:}!.  The  clay  might  have  uses  as  a  refractory  filler 
ill  face  brick  and  terra  cotta. 


Clay 
Xo. 

17 

23 

66 

67 

71 

74 

77 

79 

8f> 

87 
104 
126 
138 
140 
141 
142 
191 
192 
231 
232 
239 
244 
2.50 
270 
282 
285 


TABLE   No.   16. 

II.   Buff-Burning    Clays. 

A.   Refractory  clays,   softening  point  cone   27  4-. 

a.  Open-burning,  more  than  6</i  apparent  porosity  at  cone  15. 

5.   Low  strengtli. 


%  S.W. 

9.3 

11. S 

7.1 

5.6 

9.6 

5.6 

12.7 

5.9 

6.8 

8.0 

12.4 

13.0 

18.2 

7.8 

5.6 

6.5 

13.9 

15.4 

5.1 

8.1 

4.4 

20.4 

11.0 

11.1 

12.9 

10.7 


%  S.W. 
%  P.W. 
%  W.P. 
D.T.S. 
%  D.V.S. 
%  D.L.S. 


%  P.W. 
20.1 
19.3 
10.3 
9.0 
16.4 
23.2 
18.0 
11.7 
19.9 
14.9 
24.0 
25.4 
25.8 
IS.O 
23.0 
21.3 
30.2 
27.1 
22.8 
21.7 
13.9 
20.1 
17.4 
17.5 
17.0 
44.0 


%  W.P. 
29.4 
31.1 
17.4 
14.6 
26.0 
28.8 
30.7 
17.6 
26.7 
28.4 
36.4 
38.4 
44.0 
25.8 
28.6 
27.8 
44.1 
42.5 
27.9 
29.8 
18.3 
40.5 
28.4 
28.6 
29.9 
54.7 


D.T.S. 

136 

161 

185 

142 

131 

97 

m;190 

163 

76 

76 

178 

95 

160 

46 

92 

178 

ISO 

143 

41 

58 

50 

±190 

179 

1.S3 

±14  3 

130 


D.V.S. 
15.8 
20.3 
14.6 
11.7 
17.2 

9.1 
22.5 
11.8 
11.7 
13.5 
19.7 
19.7 
27.9 
13.5 

8.9 
10.7 
18.9 
22.0 

8.1 
13.3 

8.4 
34.1 
19.4 
19.7 
23.5 
11.8 


% 


Soften- 

ing pt. 

D.L.S. 

in  cones 

5.1 

34 

6.2 

29 

4.7 

28 

3.7 

33 

5.2 

31 

3.0 

33-34 

7.0 

30-31 

3.8 

31-32 

3.7 

33-34 

4.1 

3  4 

6.2 

35 

6.2 

33-34 

8.4 

29-30 

4.4 

32 

2.9 

34 

3.4 

33 

6.0 

30-31 

6.9 

31 

2.6 

34-35 

4.3 

34-35 

2.8 

31 

10.3 

31-32 

6.1 

31 

6.2 

32 

7.3 

33 

3.8 

30-31 

—  i>p,.  cent  shrinkage  water. 

—  Per  cent  pore  water. 
=  Per  cent  water  of  plasticity. 
=  Dry  transverse  strengtli,  i)r>uiuls  i)er  sfiiiare 
r=  Drying  shrinkage,  per  cent  dry  volume. 

=  Calculated  linear  drying  shrinkage,   per  cent  dry  length. 


inrli,  without  sand. 


284 


DIVISION  OF  MINES  AND  MINING 


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PLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


285 


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286 


DIVISION  OP  MINES  AND  MINING 


Absorption  and  linear  shrinkage  curves  for  clays  of  class  5. 


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CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  287 

(i.     .Medium  to  lli.uli  Strength. 

\o.!J  {\).\ii:i).  Riverside  County.  Alherlnll.  (".  (fc  ('.  ("o.  "  Hill  liluo." 
See  No.  271,  and  274  in  class  7,  and  272  in  tliis  class,  Avhicli  are  better 
samples  of  the  material  that  will  be  available  in  the  future.  This  is  a 
smootli,  fine  p-rained,  bulf'-burniii<i:  refractory  clay  with  prood  plasticity, 
and  medium  higli  dry  strength.  It  contains  4.S'/(>  of  +200-mesh  sand. 
It  is  used  in  art  tile,  stoneware,  terra  cotta,  and  sagger  bodies,  and 
represents  one  of  the  most  widely  used  of  the  Alberhill  clays.  The 
colors  are  pinkish  and  buffisii  white,  approximating  Kidgway's  "f" 
tone.  Finger-nail  hardness  is  developed  below  cone  010,  and  steel 
hardness  at  cone  02.  Vitrification  is  well  advanced  at  cone  13.  The 
maximum  total  linear  shrinkage,  plastic  basis,  is  13.3%  at  cone  13. 
lUoating  is  apparent  at  cone  15.  The  softening  point  is  cone  29.  The 
best  firing  range  is  from  cone  04  to  cone  13,  and  hard,  strong  bodies 
with  absorptions  below  10%  are  obtained  above  cone  3. 

No.Uiii.lG'^).  Riverside  County.  Alberhill  C.  &  C.  Co.  "A-Clay." 
This  is  a  pink  and  buff-burning  plastic  clay  used  in  the  manufacture  of 
face  brick.  It  contains  19.27o  of  -|-200-mesh  sand,  develops  excellent 
plasticity,  has  a  good  dry  structure,  and  nu'dium  high  dry  strength. 
The  colors  are:  dry,  17'"d;  wet  17"'b;  cone  010,  9'f ;  cones  08  to  04, 
5'f ;  cone  02,  ll"f;  cones  1  to  5,  13"f ;  cones  7  to  9,  17"f ;  cone  11,  17"f ; 
cone  13,  15"d.  Finger-nail  hardness  is  developed  below  cone  010,  and 
steel  hardness  at  cone  3.  The  total  linear  shrinkage,  plastic  basis,  is 
11.1%  at  cone  13.  The  softening  point  is  cone  31.  The  best  firing 
range  is  from  cone  3  to  cone  13  or  above.  A  wide  range  of  butf  and 
pink  colors  can  be  secured  in  the  normal  kiln  run. 

No.  27  (p.  163).  Riverside  County.  Alberhill  C.  &  C.  Co.  "No.  10." 
This  is  a  pale  buff-burning  clay  with  excellent  smooth  plasticity, 
medium-high  dry  strength,  and  a  medium-hard,  fine-grained,  close- 
textured  dry  condition.  It  contains  2.6%  of  -j-  200-mesh  sand.  It  is 
used  in  sagger,  art  tile  and  dry-pressed  brick  mixtures,  and  was  for- 
merly used  in  architectural  terra  cotta.  The  colors  are:  dry,  13'"f ; 
wet,  13'"k;  cones  010  to  1,  15"f ;  cone  3,  17"'f ;  beyond  cone  3,  to  cone 
15,  increasing  yellow,  decreasing  i)ink,  with  scattered  fine  brownish 
and  black  specks.  Finger-nail  hardness  appears  below  cone  010,  and 
steel  hardness  at  cone  3.  The  total  linear  shrinkage,  plastic  basis,  at 
cone  13  is  16.1%.  Bloating  is  apparent  at  cone  15.  The  softening  point 
is  cone  30-31.  The  best  firing  range  is  from  cone  3  to  cone  13.  The 
smooth  texture,  light  colors,  and  excellent  plastic,  drying  and  firing 
qualities  of  this  clay  make  it  especially  desirable  for  many  purposes. 

No.  33  (p.  205).  San  Diego  County.  Cardiff.  Vitrified  Products 
Co.  See  also  No.  34.  This  is  a  light-colored  fireclay,  of  Pleistocene  ( ">.) 
age,  containing  41.0%  of  -f-  200-mesh  sand.  It  is  used  for  fire-brick  and 
for  buff  or  cream  face  brick.  It  has  weak  plasticity  without  stickiness, 
medium-high  dry  strength,  and  in  the  dry  state  it  is  hard,  with  a 
granular  structure.  The  colors  are :  dry  and  wet,  yellowish  white ; 
cones  010  and  08,  13'"f ;  cone  06,  17'''d;  cones  04  and  02,  15"d;  cones 
1  to  13,  17"d.  These  colors,  coupled  with  a  granular  texture,  make 
pleasing  effects  for  buff  and  cream  face  brick.  Finger-nail  hardness 
appears  below  cone  010  and  the  hardness  at  cone  13  is  slightly  less  than 
steel.     The  total  linear  shrinkage,  plastic  basis,  at  cone  13,  is  8.6%. 


288  DIVISION  OF  MINES  AND  MINING 

The  softeninj?  point  is  cone  30.    The  best  firing  range  is  IVom  cone  1  to 
fibove  cone  lo. 

N(/.  .'>'/  (]).  'JO;")).  S;in  Dic^o  Coiinly.  CnrdiiT.  N'ili'ificd  I'l-odncts 
Co.  See  also  No.  'A'-i.  This  chiy  is  from  another  part  of  tlie  same  bed 
from  which  No.  33  was  taken,  and  is  similar  to  it  in  every  respect,  but 
has  less  sand,  more  iron,  strongei-  plasticity,  and  slightly  greater 
shrinkage.  It  contains  31.0%  of  -|-200-mesh  sand.  The  colors  are: 
dry,  y"'f ;  wet,  9'"d;  cones  010  to  04,  7"f ;  cone  02,  l"d;  cones  1  to  7, 
]5"d;  cones  9  and  11,  17"d ;  cone  13,  17"b.  Steel  hardness  appears 
at  cone  13.  The  total  linear  shrinkage,  plastic  basis,  at  cone  15,  is  11.5%. 
The  softening  point  is  cone  31.  The  best  firing  range  is  from  cone  1  to 
cone  15. 

No.  53  (j).  195).  San  Bernardino  County.  Hicks.  Millet  and 
Kennedy.  This  is  a  buff-burning,  plastic  fireclay  o"  Tertiary  age 
from  an  undevelojied  deposit.  The  plasticity  is  good,  the  dry  strength 
is  medium  high,  and  the  dry  condition  is  hard  and  close  grained,  with 
a  heterogeneous  texture  caused  by  the  presence  of  non-plastic  grains 
of  a  different  color  than  the  clay  portion.  The  sample  contains  10.4% 
of  -)-  200-mesh  material.  The  colors  are :  dry,  nearly  white ;  wet,  19"f ; 
cones  010  to  1,  ll"f ;  cones  3  to  9,  17'"d;  cones  11  and  13,  17'"f, 
mottled,  with  slag  spots.  Finger-nail  hardness  is  obtained  below  cone 
010,  and  steel  hardness  develops  at  cone  02.  The  fired  structure  is 
sound  throughout,  and  vitrification  is  well  advanced,  but  not  complete, 
at  cone  15.  The  maximum  total  linear  shrinkage,  plastic  basis,  at  cone 
]3,  is  20.1  *;(.  The  softening  point  is  cone  30.  The  best  firing  range  is 
from  cone  04  to  cone  13.  The  clay  is  suitable  for  the  manufacture  of 
pink  and  buff  face  brick,  and  as  a  bond  clay  in  fire  brick.  It  is  possible 
that  material  of  improved  qualitj'  can  be  found  if  the  deposit  is 
developed. 

No.76  {\).\1^).  Riverside  County.  Alberhill.  L.  A.  B.  Co.  "Gray 
No.  23."  See  No.  77,  class  5.  This  is  a  plastic  buff-burning  fireclay 
that  is  particularly  useful  in  sagger  and  pottery  mixes.  The  clay  con- 
tains 2.2%  of  +  200-mesh  sand,  the  ])lasticity  is  excellent,  the  dry 
strength  is  medium,  and  tJie  dried  condition  is  medium  hard,  fine- 
grained, and  close-textured.  The  colors  are:  dry,  17'"f;  Avet,  17'"d; 
cones  010  and  08,  7'f;  cones  06  and  04,  9'f ;  cone  02,  13"f ;  cones  1  to  13, 
17''"f,  or  slightly  whiter.  The  fired  colors  are  good  buffs  and  creams 
for  face  brick,  faience  tile,  and  similar  ])roducts.  Finger-nail  hard- 
ness is  developed  below  cone  010,  and  steel  hardness  at  cone  1.  The 
fired  structure  is  sound  and  stony,  and  smooth  textures  are  obtained. 
Absorptions  below  10%  are  obtained  at  cone  9.  The  maximum  total 
linear  shrinkage,  plastic  basis,  is  15. 6*;;,  at  cone  11.  The  softening 
point  is  cone  29.    The  best  firing  range  is  from  cone  1  to  cone  13. 

No.   78    (p.   174).       Riverside   County.       Alberhill.       L.   A.   B.   Co. 

'No.  10."  This  is  a  dark  colored,  butt'-burning,  plastic  fireclay,  con- 
taining carbonaceous  matter.  It  is  used  for  fire  brick  and  face  brick. 
The  sample  contains  16.2%  of  +  200-mesh  sand.  The  plasticity  is 
excellent,  the  dry  strength  is  medium-high,  and  the  dried  condition  is 
medium-hard,  medium  fine-grained  and  close-textured.  The  colors  are : 
dry,  13'"'d;  wet,  13""i ;  cones  010  to  04,  9'f;  cone  02,  13''f;  cones  1 
to  13,  between  17"'f  and  21"'f,  although  slightly  whiter  at  some  cone 


<<i 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  289 

luiiiibcrs.  Scattered  yellowish  speeks  apjx'ar  at  low  firin<i'  temperatures, 
which  darken  and  become  more  ijrominent  at  hij>li  temperatures. 
P'infrer-nail  haiduess  appears  below  cone  010,  and  steel  hardness  at 
cone  1.  Absoi-ptions  above  lO'y  are  found  above  cone  8.  The  fired 
strneture  is  sound  and  above  cone  02  is  stony.  The  total  linear  firing 
slii-iidcage,  phistic  basis,  at  cone  13,  is  IT.l^r.  Slight  bloating-  w^as 
noted  at  cone  L'v  The  softening  i)oint  is  cone  29.  The  best  firing 
range  is  from  eone  1  to  cone  13.  The  plasticity,  dry  and  fired  strength, 
and  wide  vitrification  range  at  commercially  attainable  temperatures 
are  the  most  valuable  properties  of  this  clay. 

Xa.  81  (]).  174).  Riverside  County.  Alberhill.  L.  A.  li.  Co. 
"No.  25."  This  is  a  i)lastic  fireclay,  similar  to  No.  76,  but  with  more 
coloring  matter,  and  a  higher  jn-oportion  of  clay  substance.  It  is  used 
for  face  brick  and  fire  brick.  It  contains  oidy  1.8'/^  of  +200-mesh  sand, 
the  plasticity  is  smooth  and  strong,  the  dry  strength  is  medium  high, 
and  the  drv  condition  is  medium  soft,  fine-grained,  and  close-textured. 
The  colors ^are:  dry,  17'"f;  Avet,  17'"b ;  cones  010  to  1,  ll'd;  cones  3 
and  5,  ll'f ;  cones  7  to  11,  17'"f ;  cone  13,  17"f.  These  are  suitable 
butfs  and  tans  for  face-brick  manufacture.  Finger-nail  hardness 
appears  below  cone  010,  and  steel  hardness  at  cone  1.  Absorptions 
below  10%  are  obtained  at  cone  7  and  above.  The  total  linear  shrink- 
age, ])lastic  basis,  at  cone  13,  is  15.8%  .  The  softening  j^oint  is  cone  28. 
The  best  firing  range  is  above  cone  1. 

No.  84  (p. 174).  Riverside  County.  Alberhill.  L.  A.  B.  Co.  "Main 
Pit  Fireclay."  This  is  a  i)lastic  fireclav,  similar  to  the  "Main  Tunnel" 
clavs  mined  bv  the  Alberhill  C.  &  Co.  Co.  and  by  G.,  McB.  &  Co., 
see  samples  No.  15,  29,  90,  and  93  in  class  2,  and  No.  13  and  229  in 
class  7.  It  contains  11.0%  of  +200-mesli  sand,  the  ])lasticity  is  smooth 
and  strong,  the  dry  strength  is  medium,  and  the  dry  condition  is  soft, 
fine-grained,  and  close-textured.  The  colors  are:  dry,  17"'f;  Avet, 
]7"'d;  cones  010  to  13,  9'f  to  17'f.  Green  staining  is  pronounced. 
Finger-nail  hardness  develops  below  cone  010,  and  steel  hardness  at 
cone  3.  Less  than  10%  absor])tion  is  obtained  at  cone  5.  Vitrification 
is  well  advanced  at  cone  13.  With  the  exception  of  a  few  cracks  that 
resulted  from  the  rapid  fii'ing  schedule  used,  the  fired  test  jiieces  are 
sound.  The  total  linear  shrinkage,  plastic  basis,  at  cone  13  is  12.2%. 
The  softening  point  is  cone  28.  The  best  firing  range  is  above  eone  3. 
The  clay  may  be  used  in  fii'c  hiick,  face  brick,  faience  tile,  stoneware, 
and  pottery  mixes.    The  color  is  not  white  enough  for  whiteware  bodiea 

No.  92  (p.  171).  Riverside  County.  Alberhill.  G.,  McB.  &  Co. 
"Yellow  Main  Tunnel  Clay."  This  is  a  i)lastic,  butf-burning  clay 
that  can  be  used  in  fire  brick  ami  face  brick.  It  contains  16.8%  of 
+200-mesh  sand.  The  ])lasticity  is  smooth  and  strong,  the  dry  strength 
is  medium-high,  and  in  the  dried  state  it  is  medium  hard,  fine-grained, 
and  close-textured.  The  colors  are:  dry,  17"d;  wet,  17";  cones  010 
to  02,  7'd;  cones  1  to  7,  7'f;  cones  9  to  V.\,  17"d.  Scattered  slag 
spots  appear  above  cone  9.  Finger-nail  hardness  appears  below 
cone  010,  and  steel  hardness  at  cone  1.  Absorptions  under  10% 
are  found  at  cone  11.  The  fired  structure  is  sound,  and  at  high  tem- 
])eratures,  is  stony.  The  total  linear  shrinkage,  plastic  basis,  at  cone 
13,  is  13.6%c.    The  softening  point  is  cone  28. 

19 — 54970 


290  DIVISION  OF  MINES  AND  MINING 

No.  97  (p.  171).  Riverside  Connty.  Alberhill.  G.,  Me.B.  &  Co. 
"Smooth  Bunker."  Thi.s  is  a  hufir-bnrniiif!:  terra  eotta  clay  with  excel- 
lent plasticity  and  medium  higrli  dry  strengrth.  Tlu^re  is  slight  ett'er- 
vescence  in  hydrochloric  acid.  In  tlie  dried  condition  it  is  soft,  fine- 
grained, and  close-textured.  Tt  conlains  15.6%  of  +200-mesli  sand. 
The  colors  are:  drv,  13""d;  wet,  17""d;  fired,  from  cone  010  to  cone 
13,  13"f  to  17'"f.  ^  The  color  at  cone  13  is  deeper  than  in  No.  96  (class 
3),  and  a  few  iron  specks  appear  which  are  not  present  in  No.  96. 
Finger-nail  hardness  appears  below  cone  010,  and  steel  hardness  at 
cone  02.  The  fired  structure  is  sound  and  stony,  and  the  texture  is 
.^lightly  rough.  Absorptions  under  lO.O'/r  are  obtained  at  cone  11.  The 
total  linear  shrinkage,  pla.stic  basis,  at  cone  13,  is  11.4%.  The  soften- 
ing point  is  cone  31.     The  best  firing  range  is  from  cone  1  to  cone  13. 

No.  102  (p.  171).  Riverside  County.  Alberhill.  G.,  McB.  &  Co. 
"Sloan  Sand."  This  is  a  sandy  fireclay  witli  fair  plasticity,  medium 
dry  strength,  and  a  medium-hard,  medium-grained,  open-textured  dried 
condition.  It  contains  30.6%  of  -}-200-mesli  sand.  The  colors  are : 
dry,  17"f ;  wet,  15";  cones  010  to  02,  9"b;  cone  1,  9"d;  cones  3  to  11, 
13"d;  cone  13,  17"d.  At  cones  11  and  13,  scattering  gray  and  brown 
specks  appear.  Finger-nail  hardness  appears  below  cone  010,  and  steel 
hardness  develops  at  cone  3.  The  fired  condition  is  sound,  granular, 
and  rough-textured.  The  total  linear  shrinkage,  plastic  basis,  at  cone 
13,  is  9.7%.  The  softening  point  is  cone  29.  The  clay  is  suitable  for 
the  manufacture  of  face  brick,  and  as  an  ingredient  in  low-grade  fire- 
brick mixes. 

No.  108  {p.  \1^).  Riverside  County.  Alberhill.  Pacific  Clay  Products 
Co.  "Tapper  Douglas."  Tliis  is  a  deep  buflf-burning  sewer-pipe  clay 
with  good  plasticity,  high  dry -strength,  and  in  the  dried  condition  it 
has  finger-nail  hardness,  and  a  fine  grained  and  close  texture.  It  con- 
tains 5.8%  of  -)-200-mesh  sand.  The  colors  are:  drv,  17"f;  wet, 
13"d;  cones  010  to  02,  ll'd;  cone  1,  15'd;  cones  3  to  13^,  15"d.  Steel 
hardness  is  developed  at  cone  1.  Less  than  \Q%  absorption  is  developed 
at  cone  3.  Vitrification  is  complete  at  cone  11,  after  which  bloating 
begins.  The  fired  structure  is  sound  and  stony.  The  maximum  total 
linear  shrinkage,  plastic  l)a.sis,  is  20.0%,  at  cone  11.  The  softening 
point  is  cone  27-28. 

No.  130  (p.  62).  Amador  County.  Toiu\  "Newman  Carbonaceous 
Sand."  This  is  a  fire  sand  high  in  carbonaceous  matter  for  which  no 
uses  have  been  found.  Some  iron  compounds  are  present  which  are 
partly  soluble  in  the  mixing  water,  and  cause  discoloration  by  efflor- 
escence. The  residue  on  200-mesh  is  16.0%.  More  clay  is  present  than 
in  No.  129  (class  1),  resulting  in  better  plasticity,  and  medium  dry 
strength.  The  interior  colors  are:  drv,  15'""b;  wet,  15""m;  cones 
010  to  1,  15"b;  cones  3  to  5,  13"b;  cones  7  and  9,  13"b.  The  efflor- 
escence has  a  5'i  color  from  cone  010  to  cone  1.  Steel  hardness  is 
approximated  at  cone  3.  Tlie  fired  structure  is  sound,  fine-grained,  and 
open  textured.  Light  hair-cracks  appear  on  the  surface  of  test  pieces 
fired  above  cone  3.  The  total  linear  shrinkage,  plastic  basis,  at  cone  9, 
is  11.6%.     The  softening  point  is  cone  27. 

No.  139  (p.  52).  Amador  County.  lone.  M.  J.  Bacon.  "Bacon 
Blue."     This   is   a   fine-grained,   cream-burning,    plastic   clay   that   is 


CLAY  RESOURCES  AXD  (■EKA>tIi'   IXDUSTRY  291 

suitable  for  stoneware  maiinfactiire.  It  contains  1.4%  of  -f-200-mesh 
sand.  The  plasticity  is  very  grood,  the  dry  strenprth  is  niedinni  Ioav,  and 
\u  the  drii^l  coiidilion  il  is  niediiiin-hard.  fiiic-^nviined,  and  open- 
textured.  The  c<)h)rs  are:  dry,  l:5""f;  wet,  17""f;  cone  010,  17"f, 
changiuf?  to  pinkish  white  at  cone  02,  then  to  cream-white  up  to  cone 
9;  cones  11  and  13,  19"d.  Fiufrer-iuiil  hardness  is  approximated  at 
cone  010,  and  steel  liardness  develops  at  cone  7.  Less  than  10% 
ab.sorption  is  developed  at  cone  9.  The  fired  structure  is  sound  and 
stony,  and  the  surface  texture  is  smooth.  The  total  linear  shrinka<?e, 
plastic  basis,  at  cone  13,  is  17.7%.  Bloating  is  pronounced  at  cone  15. 
The  softening  point  is  eone  29-30.  TIk^  liest  firing  range  is  from  cone 
5  to  cone  11. 

Xo.  145  (p.  156).  Placer  County.  Lincoln.  Liiu-oln  ("lay  Products 
Co.  "Xo.  0."  This  variety  of  the  Lincoln  clay  contains  a  large  i)ro- 
portion  of  sand,  and  enough  iron  to  give  buff  and  pink  colors  on  firing. 
It  effervesces  slightly  in  hydrochloric  acid.  The  ])lastieity  is  good,  the 
dry  strength  is  medium-high,  and  in  the  dried  coiulition,  it  is  medium 
soft,  medium-grained,  and  open-textured.  The  colors  are:  dry,  17"f; 
wet,  17"d;  cones  010  to  02,  ll'f ;  cones  1  to  5,  13'f ;  cones  7  to  13,  17'f. 
Steel  hardness  is  develoj)ed  at  cone  1.  Less  than  10%  absorption 
appears  at  cone  9.  The  fired  structure  is  sound,  and  consists  of  sand 
particles  imbedded  in  a  clay  ground  mass.  The  fired  surface  texture 
is  rough,  and  at  high  firing  temperatures,  the  surface  is  mottled.  The 
maxinuim  total  linear  shrinkage,  plastic  basis  is  17.7%  at  cone  13. 
Sligiit  bloating  develops  at  cone  15.  The  softening  point  is  cone  30-31. 
The  best  firing  range  is  from  cone  1  to  cone  13.  The  clay  is  used  in 
face  brick  mixes,  and  could  be  used  for  the  cheaper  grades  of  fire  brick, 
and  in  terra  cotta. 

No.  150  (p.  156).  Placer  County.  Lincoln.  Lincoln  Clay  Products 
Co.  "Xo.  10."  For  all  practical  purposes  this  clay  is  identical  to  Xo. 
149  (class  7)  although  the  dry  strength  is  25%  higher,  and  the  porosi- 
ties are  somewhat  higher.  Xo  blistering  can  be  detected  when  fired  to 
cone  13,  but  bloating  is  apparent  at  cone  15.  The  total  linear  shrink- 
age, plastic  basis,  at  cone  13,  is  20.6%.    The  softening  point  is  cone  32. 

No.  197  (p.  227).  Sonoma  County.  Two  miles  east  of  Beltane. 
This  clay,  from  an  undeveloped  deposit,  has  good  plasticity,  but  with 
a  tendency  to  sponginess,  medium-high  dry  strength,  and  in  the  dried 
condition  it  has  finger-nail  hardness,  is  fine-grained,  and  open-textured. 
A  tendency  to  crack  during  drying  was  noted.  The  colors  are:  dry, 
yellowish  white;  wet,  19"f  (yeilow-bulf)  ;  cones  06  and  02,  17"f ;  cone 
1,  17"b ;  cone  3,  17"d.  The  fired  colors  are  too  yellowish  for  good  face- 
brick  effects.  Steel  hardness  was  not  develoi)ed  at  cone  3,  which  was 
the  highest  temperature  studied.  The  fired  structure  is  sound.  The 
total  linear  shrinkage,  plastic  basis,  at  cone  3,  is  12.3%.  The  softening 
point  is  cone  27-28.  More  data  are  needed  before  a  prediction  of  pos- 
sible uses  can  be  made,  but  the  clay  seems  Avorthy  of  further  investiga- 
tion. 

No.  257  (p.  52).  xVmador  Co\mty.  lone.  Core  drill  hole  Xo.  62, 
Arroyo  Seco  Grant.  This  is  one  of  the  best  of  the  core-drill  samples 
that  were  tested.  The  plasticity  is  good,  with  a  tendency  to  stickiness, 
the  dry  strength  is  medium  high,  and  in  the  dried  condition  it  is  medium- 


292  DIVISION  OP  MINES  AND  MINING 

hard,  fine-grained,  and  close-textured.  There  is  slig^ht  effervescence  in 
liydrochlorie  acid.  The  colors  are:  dry,  17""d;  wet,  13""k;  cone  1, 
nearly  white;  cones  ")  and  J),  buff-wliite;  cone  13,  17"f.  Steel  hardness 
is  developed  l)etween  cone  1  and  cone  5,  and  less  tlian  10% 
absorption  between  cones  9  and  13.  The  fired  structure  is  .sound  and 
stony,  and  the  surface  texture  is  smooth.  The  total  linear  shrinkage, 
plastic  basis,  at  cone  13,  is  18.7 /f .  The  softening  ])()int  is  cone  31-32. 
Tins  clay  is  suitable  as  a  refractory  bond  clay  in  fire  brick,  terra 
cotta,  and  tile,  and  might  be  u.sed  in  stoneware  bodies. 

No.  258  (p.  52).  Amador  County.  lone.  Core  drill  hole  No.  61, 
Arroyo  Seco  Grant.  This  is  a  sandy  clay  containing  a  large  propor- 
tion of  ferro-magnesian  mineral  grains.  The  residue  on  200-mesh  is 
18.8%.  The  plasticity  is  fair,  but  sticky,  the  dry  strength  is  medium, 
and  in  the  dried  condition  it  is  medium-hard,  medium-grained,  and 
open-textured.  The  colors  are:  dry,  grayish  white;  wet,  l'""f ;  cones 
1  and  5,  17"f;  cone  9,  17"d ;  cone  13,  17"b.  At  cone  9  and  above, 
numerous  slag  pits  appear.  Steel  hardness  is  developed  between  cones 
1  and  5,  and  less  than  IQ'/i  absorption  slightly  above  cone  5.  The  fired 
structure  is  sound,  moderately  strong,  and  granular.  The  total  linear 
shrinkage,  plastic  basis,  is  14.2%,  at  cone  13.  The  softening  point  is 
cone  28-29. 

No.  263  (p.  159).  Placer  County.  East  of  Lincoln.  Valley  View 
Mine.  This  is  a  plastic  kaolin  that  burns  nearly  white.  It  contains 
1.2%  of  +  200-mesh  material.  The  plasticity  is  good,  but  Avith  a 
tendency  to  stickiness,  the  dry  strength  is  medium  high,  and  in  the 
dried  condition  it  is  medium-hard,  fine-grained,  and  close-textured. 
The  colors  are-  dry,  pinkish  white;  vret,  17"f ;  cones  08  and  04,  15"f ; 
cone  1,  whiter  than  17"f ;  cones  7  and  13,  slightly  whiter  than  17'"f. 
It  can  nearly  be  classed  as  a  white-burning  clay.  Steel  hardness  is 
developed  at  cone  7  and  less  than  10';^  absorption  at  cone  9  (approx). 
The  fired  structure  is  sound,  stony,  and  smooth-textured.  The  total 
linear  shrinkage,  plastic  basis,  is  21.4%,  at  cone  13.  The  softening 
point  is  cone  32-33.  This  clay  is  suitable  for  use  in  terra  cotta.  Avail 
tile,  and  possibly  in  fire  brick. 

No.  266  (]).  140).  American  Refractories  Co.  "Amreco  Fire  Clay." 
This  is  a  sample  of  fireclay  from  which  the  "Amreco"  brand  fire  brick 
is  manufactured.  It  contains  32.8%  of  +  200-mesh  sand.  The  plas- 
ticity is  excellent,  the  dry  strength  is  medium,  and  in  the  dried  condi- 
tion it  is  medium-hard,  medium-grained,  and  medium-textured.  The 
colors  are:  dry,  17'"d;  wet,  13"'b;  cones  010  to  06,  9"f;  cone  04, 
15"f,  first  fading  with  increasing  temperature,  then  becoming  more 
yellowish;  cones  11  and  13,  ]7'"f.  Slight  mottling  is  produced  at 
high  temperatures  by  the  presence  of  iron  minerals.  Steel  hardness 
is  developed  at  cone  !).  The  fired  structure  is  sound  and  moderately 
strong.  The  .surface  texture  is  slightly  rough.  The  total  linear 
shrinkage,  plastic  basis,  at  cone  15,  is  11.8%.  The  softening  point  is 
cone  32. 

No.  272  (p.  163).  Riverside  County.  Alberhill.  A.  C.  &  C.  Co. 
"Main  Tunnel  Hill  Blue."  See  also  No.  9  in  this  class  and  No.  271 
and   274   in   class   7.      This   sample   contains   more   sand   and   fluxing 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


2<)3 


impurities  than  the  other  three  sami>les  of  "Hill  Blue"  clay.  The 
percenta^'e  of  -f-200-mesh  sand  is  87.0.  The  plasticity  is  good,  the  dry 
strength  is  medium,  and  in  the  dried  condition  it  is  medium-hard, 
coarse-grained,  and  open-textured.  There  is  slight  effervescence  in 
livdroelilorie  acid.  The  eoh)rs  are:  dry,  18""f ;  wet,  15"'"f ;  cones  010 
to  1,  13''f ;  cones  3  to  9,  17"f ;  cones  11  and  13,  17"d.  Steel  hardness 
and  less  than  10%  absorption  are  developed  at  cone  11.  A  mottled  and 
heterogeneous  fired  .structure  is  produced  by  tlie  ]U'esence  of  a  large 
percentage  of  ferro-magnesian  minerals.  The  fired  structure  is  sound, 
and  the  surface  texture  is  rough.  The  total  linear  shrinkage,  plastic 
basis,  at  cone  13,  is  9.8%.    The  softening  point  is  cone  29. 


Clay 

No. 

9 

14 

27 

33 

34 

53 

76 

78 

81 

84 

92 

97 
102 
108 
130 
139 
145 
150 
197 
257 
258 
263 
266 
272 


TABLE    No.   18. 
II.   Buff-Burning    Clays. 

A.   Refractory  clays,  softening  point  cone  27 -f. 

a.  Open-burning,  more  than  6%  apparent  porosity  at  cone   15. 

6.   Medium  to  higli  strength. 


%  S.W, 
12.6 
11.6 
15.5 
10.6 

9.0 
25.2 
13.5 
17.4 
16.7 
11.4 
15.0 
11.8 

9.9 
27.1 
14.2 
16.5 
17.4 
20.7 
33.7 
2i.8 

9.7 
21.5 

8.9 
10.2 


%  P.W. 
13.3 
12.4 
14.8 
11.4 
13.6 
19.1 
18.1 
19.4 
16.8 
12.7 
13.5 
14.1 
14.0 
13.1 
22.9 
17.8 
21.0 
18.5 
31.9 
19.5 
16.1 
20.0 
15.2 
12.5 


Soften- 

ing pt. 

'c  W.P. 

D.T.S. 

%  D.V.S. 

%  D.L.S. 

in  cones 

25.9 

770 

24.8 

7.7 

29 

24.1 

420 

22.6 

6.9 

31 

30.3 

458 

28.6 

8.6 

30-31 

22.0 

550 

20.7 

6.4 

30 

22.6 

449 

17.5 

5.5 

31 

44.3 

795 

42.4 

12.3 

30 

31.6 

240 

23.9 

7.4 

29 

36.8 

462 

29.1 

8.8 

29 

33.5 

414 

30.0 

9.1 

28 

24.1 

326 

22..-. 

7.0 

28 

28.5 

480 

28.8 

S.7 

28 

25.9 

412 

22.3 

7.0 

31 

23.9 

271 

19.0 

6.0 

29 

40.2 

-t-1118 

52.3 

15.0 

27-28 

37.1 

3S7 

22.5 

7.1 

27 

34.3 

201 

28.7 

8.7 

29-30 

38.4 

447 

29.1 

7.8 

30-31 

39.2 

337 

35.7 

10.7 

32 

65.6 

529 

44.9 

13.2 

28 

41.3 

403 

36.7 

11.0 

32 

25.8 

217 

18.1 

.-).7 

28-29 

41.5 

417 

36.2 

10.8 

32-33 

24.1 

231 

16.4 

5.2 

32 

22.7 

348 

19.8 

6.2 

29 

%  S.W.  =  Per  cent  shrinkage  water. 

%  P.W.  =  Per  cent  pore  water. 

%W.P.  =  Per  cent   water  of  plasticity. 

i).T.S.  =  Dry  transverse  strength,   pounds  per  square   inch,   without  sand. 

%  D.V.S.  =  Drying  shrinkage,   per  cent   dry   volume. 

%  D.L.S.  =  Calculated  linear  drying  shrinkage,  per  cent  dry  length. 


594 


DIVISION  OF  MINES  AND  MINING 


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CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


295 


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b.  Dense-Burning,  Less  Than  6%   Apparent  Porosity  Between 

Cones  10  and  15. 

7.  Mainly  Medium  to  High  Strength. 

No.  13  (p.  163).  Riverside  Conntv.  Alberhill  C.  &  C.  Co.  "Extra 
Select  :Main  Tunnel."  See  also  No.  15  and  29  in  class  2.  This  clay 
is  hand  sorted  from  the  main  tunnel  fireclay  bed,  in  order  to  prepare 
a  grade  for  the  market  that  has  better  fired  colors  than  the  run-of-mine 
material,  but  for  some  undetermined  reason  the  sample  is  distinctly 
inferior  as  to  color,  compared  to  No.  15  and  29.  It  is  used  principally 
in  the  manufacture  of  art  tile,  and  to  some  extent  in  firebrick.  It  has 
excellent  plasticity,  medium  dry  strength,  and  a  sandy,  open  texture 
in  the  drv  condition.  It  contains  2.6' r  of  -|-200-mesh  sand.  The  colors 
are:  dry,  17'"^f;  wet,  17'"'b;  cones  010  to  06,  ll'f;  cone  01,  17"f; 
cones  02  to  18,  17"'19'"f.  Finger-nail  hardness  is  developed  below 
cone  010,  and  steel  hardness  is  approached  at  cone  7,  but  vitrification 
is  not  complete  until  cone  15  is  reached.  The  total  linear  shrinkage, 
plastic  basis  is  14.5%  at  cone  15.  The  softening  point  is  cone  29-30. 
The  best  firing  range  is  from  cone  7  to  cone  15. 

.Vo.  55  (p.  203).  San  Diego  County.  Near  Carlsbad.  Pacific  Clay 
Products  Co.  "Kelley  Ranch  White."  Tliis  is  a  butf-burning  clay  with 
excellent  plasticity,  suitable  for  the  manufacture  of  face  brick  and 
fire  brick.  It  contains  2.6/r  of  +200-mesh  sand,  has  medium  dry 
strength,  and  in  the  dry  state  it  is  soft,  fine-grained,  and  dense.  The 
colors  are:  dry,  11";  wet,  5";  cones  010  to  01.  7"f;  cone  02,  5"f; 
cone  1,  9"f ;  cone  3,  13"f ;  cones  5  and  7,  17"f ;  cones  9  and  11,  17"d; 
cone  13,  15"d.  A  pleasing  assortment  of  buffs,  creams,  and  yellow- 
browns  is  obtained  by  varying  the  firing  conditions.  Finger-nail  hard- 
ness is  obtained  below  cone  010,  and  steel  hardness  develops  at  cone  1. 
The  fired  structure  is  sound,  fine-grained,  and  above  cone  1,  it  is  stom-. 


CLAY  RESOURCES  AND  CERAMIC   INDUSTRY  297 

The  total  linear  shriiikajie,  ])]astie  basis,  at  cone  15  is  17.99r.  The 
softeninff  point  is  cone  29.  The  best  firinfj  range  is  from  cone  1  to 
cone  1"). 

Xo.  56.  German  fireclay,  used  by  Atlas  Fire  Brick  Co.  This  is 
a  fine-<rrained  clay  with  a  smooth  and  stronji'  i)lasticity,  medium- 
hi{rii  dry  strength,  and  a  hard,  fine-grained,  close-textured  dry  con- 
dition, with  a  slight  tendency  to  laminate.  It  contains  2.8'/^  of  -|-200- 
mosh  sand.  The  colors  are:  dry,  whiter  than  17""f  wet,  17""f ;  cones 
010  to  1,  somewhat  whiter  than  17"'f ;  cones  3  and  5,  19"f ;  cones  7  to 
18,  17" 'f.  The  fired  structure  is  stony,  and  with  the  firing  schedule 
used,  one  or  more  large  cracks  developed  in  many  of  the  test  pieces. 
Finger-nail  hardness  develops  below  cone  010,  and  steel  hardness  at 
cone  06.  Absori)tions  below  10.0%  appear  at  cone  1.  The  total  linear 
shrinkage,  plastic  basis,  at  cone  13,  is  11.9%.  The  softening  point  is 
cone  27.  The  best  firing  range  is  from  cone  06  to  cone  13  and  above. 
The  clay  is  particularly  well  suited  for  use  as  a  firebrick  bond. 

Xo.  80  (p.  174).  Riverside  County.  Alberhiil.  L.  A.  B.  Co.  "Plastic 
Pink  and  Yellow."  This  is  a  buff  and  gray-burning  refractory  clay, 
containing  but  2.6'^  of  -|-200-mesh  sand,  and  with  smooth  and  strong 
plasticity.  The  dry  strength  could  not  be  accurately  determined  with- 
out adding  sand,  as  incipient  lines  of  weakness  are  developed  during 
air-drying.  With  50 /(  of  —  20-mesli  to  -|-30-mesh  Ottawa  sand,  the 
bonding  strength  is  56  lb.  per  s(|.  in.  In  the  dried  condition,  it  is  medium 
soft,  fine-grained,  and  close  textured.  The  colors  are:  drv,  13"d ;  wet, 
13";  cones  010  to  04,  7'd ;  cones  02  to  5,  7"d ;  cone  7,  9"'f;  cones  9  to 
13,  17""f.  Steel  hardness  is  developed  below  cone  010,  absori)tions  of 
less  than  lO'/f  are  i)resent  at  cone  3  or  above,  and  vitrification  is  com- 
plete at  cone  9.  All  fired  test  pieces  are  severely  shattered,  and  broken 
into  several  pieces.  The  fired  structure  is  stony  and  brittle.  The 
maximum  total  linear  shrinkage,  plastic  basis,  was  noted  at  cone  9, 
25.0% ,  but  on  account  of  the  serious  shattering  of  the  test  pieces  at 
cones  11  and  13,  which  invalidated  the  accuracy  of  measurement,  it  is 
likely  tliat  the  true  value  of  the  shrinkage  at  these  latter  temperatures 
is  higher  than  at  cone  9.  The  softening  point  is  cone  33.  The  clay  is 
similar  in  many  respects  to  No.  273  in  class  3  (Alberhiil  SII-4),  except 
that  it  contains  more  iron.  It  is  a  useful  bond  clay  in  buff-burned  ware, 
but  can  not  be  used  alone. 

Xo.  83  (p.  114).  Riverside  County.  Alberhiil.  L.  A.  B.  Co.  "Main 
Pit  Red."  This  is  a  pla.stic,  light-re(l-l)uriiing  clay  of  value  in  the 
manufacture  of  roofing  tile,  face  brick,  hollow  building  tile,  and  similar 
products.  It  contains  11.69^  of  -|-200-mesli  sand,  and  has  a  smooth 
and  strong  plasticity.  The  dry  strength  is  medium,  and  the  dried 
condition  is  medium  hard,  dense,  and  fine-grained.  The  colors  are: 
dry,  5"b;  wet,  5";  cones  010  to  02,  5'd;  cones  1  to  5,  7'd;  cones  7  to 
13,  ll"d.  Finger-nail  hardness  appears  below  cone  010,  and  steel 
hardness  at  cone  1.  Absor])tious  below  10%  a))pear  at  cone  5.  The 
fired  structure  is  dense  and  stony,  and  is  sound  up  to  cone  3.  At 
higher  temperatures,  the  test  pieces  are  broken  into  two  or  three 
pieces.  The  total  linear  shrinkage,  plastic  basis,  at  cone  13,  is  18.3%. 
The  softening  point  is  cone  29.  The  best  firing  range  is  from  cone  1 
to  cone  5,  but  slow  firing  to  cone  13  Avill  doubtless  result  in  sound 
structures  and  thorough  vitrification. 


298  DIVISIOX  OF  MINES  AND  MINING 

A"o.  85  (p.  174).  Riverside  County.  Alberhill.  L.  A.  B.  Co.  "Pink 
Mottled."  Til  is  is  a  plastic,  bulT-burning  clay  that  has  wide  uses  in 
sewer-pipe,  hollow-tile,  pottery,  flower  pot,  and  face  brick  mixes.  The 
plasticity  is  excellent,  the  dry  strength  is  medium,  and  the  dry  con- 
dition is  soft  and  fine-grained.  It  contains  3.4%  of  4-200-mesh  sand. 
A  tendency  to  laminate  was  noted.  The  colors  are :  drj%  7"d ;  wet, 
9"b;  cones'OlO  to  04,  9'b;  cone  02.  7'd ;  cones  1  to  5,  7'f ;  cone  7,  ll'f ; 
cones  9  to  18,  13'f.  Finger-nail  hardness  is  developed  below  cone  010, 
and  steel  hardness  at  cone  1.  Less  than  10%  absorption  is  present  at 
cone  7.  The  total  linear  shrinkage,  plastic  basis,  at  cone  13,  is  18.3%. 
The  softening  point  is  cone  31-32.    The  best  firing  range  is  above  cone  1. 

No.  101  (p.  171).  Riverside  County.  Alberhill.  G.,  :\IcB.  &  Co. 
"Sloan  White."  This  is  a  bulf -burning  face  brick  or  fire  brick  clay  with 
excellent  plasticity,  medium  dry  strength,  and  a  medium  hard,  fine- 
grained, close-textnred,  drv  condition.  It  contains  7.0%  of  -{-200- 
mesh  sand.  The  colors  are:  drv,  17'"f ;  wet,  17""d;  cones  010  to  02, 
9''d ;  cone  1,  13''f ;  cones  3  to  11,  17''f ;  cone  13,  17"d.  Finger-nail  hard- 
ness appears  below  cone  010,  and  steel  hardness  develops  at  cone  3.  The 
fired  condition  is  sound,  stony,  and  smooth-textured.  The  total  linear 
shrinkage,  plastic  basis,  at  cone  15  is  17.5%.  The  softening  point  is 
cone  30. 

No.  110  (p.  176).  Riverside  County.  Alberhill.  P.  C.  P.  Co.  "Doug- 
las." This  is  a  plastic  fireclay,  similar  to  No.  104  (class  5)  but  not 
quite  so  refractory.  It  is  also  related  to  No.  27  (class  6)  and  No.  273 
(class  3),  but  differs  from  these  in  several  important  respects,  as  will  be 
noted  by  a  close  study  of  the  data.  It  contains  3.4%  of  -f  200-mesh 
sand.  The  plasticity  is  very  good,  the  dry  strength  is  medium,  and  the 
dried  condition  is  medium-hard,  fine-grained,  and  close-textured.  The 
colors  are :  dry,  13""b ;  wet,  13"" ;  cones  010  to  02,  7"d ;  cones  1  and  3, 
7"f ;  cone  5,  i7"f ;  cones  7  to  11,  21"'f ;  cone  13  slightly  darker  than 
cone  11.  Steel  hardness  develops  at  cone  06.  Absorptions  below  10% 
develop  at  cone  3  and  above.  All  fired  test  pieces  are  badly  shattered, 
and  broken  into  two  or  more  pieces.  The  texture  is  smooth,  and 
peppery  with  finely  divided  specks  of  iron.  The  total  linear  shrinkage, 
plastic  basis,  at  cone  13,  is  22.5%.  Slight  bloating  was  noted  at  cone 
15.  The  softening  point  is  cone  32-33.  The  clay  is  used  for  stone- 
Avare  and  pressed  brick. 

No.  133  (p.  63).  Amador  County.  lone  (Carbondale).  Yos.  P.  C. 
Co.  "Harvey  Clay."  This  is  a  buff -burning  fireclay  with  good 
plasticity,  medium-low  dry  strength,  and  a  medium-hard,  fine-grained, 
close-textured  dried  condition.  It  contains  6.8%  of  -|-200-mesh  sand. 
The  colors  are:  drv,  9""f :  wet.  5""d ;  cones  010  to  06,  13"f ;  cones  04 
to  1,  17'"f ;  cones  3  to  7,  19"f ;  cone  9,  21'"f ;  cones  11  and  13,  17""f. 
Steel  liardne.ss  develops  at  cone  1,  and  less  than  10%  absorption  at 
cone  3.  The  fired  structure  is  stony  and  sound,  except  at  cones  11  and 
13,  at  which  small  tension  cracks  ajjjH'ar.  Blistering  is  noticeable  at 
cone  13.  The  maximum  total  linear  shrinkage,  plastic  basis,  is  24.5% 
at  cone  11.  The  softening  point  is  cone  33.  The  best  firing  range  is 
from*  cone  1  to  cone  11.  The  clay  may  be  used  in  fire  brick,  terra  cotta, 
face  brick,  etc. 

No.  149  (p.  156).    Placer  County.    Lincoln.    Lincoln  Clay  Products 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  299 

Co.  "No.  9."  This  clay  is  .similar  to  No.  14G  in  class  8,  but  does  not 
vitrify  so  completely  at  cones  9  to  13,  nor  can  blistering  be  detected  at 
cone  13,  but  bloatinjr  is  apparent  at  cone  15.  The  total  linear  shrinkage, 
plastic  basis,  at  cone  13,  is  19.9 '^t.    The  softening  point  is  cone  31-32. 

No.  153  (p.  147).  Placer  County.  Lincoln.  Clay  Corporation  of  Cali- 
fornia. See  No.  152  and  280  in  class  8.  This  sample  has  lower  refrac- 
toriness, slightly  more  sand,  and  more  coloring  matter  than  No.  152.  It 
contains  25.0%  of  +200-mesh  sand.  The  plasticity  is  excellent,  tlie  dry 
strength  is  medium-high,  and  in  tlic  dried  condition  it  is  medium-hard, 
medium-graiiu'd,  and  open-te.xtured.  The  colors  are:  dry,  21'"f ;  wet, 
19"d ;  cones  010  to  1,  ll'd ;  cones  3  and  5,  15'M ;  cones  7  to  13,  17''d. 
Steel  hardness  is  deveh)ped  at  cone  1.  Less  than  10%  absorption 
appears  at  cone  7.  The  fired  structure  is  sound,  stony,  and  the  fired 
.surface  texture  i.s  sligldly  rougli.  The  maximum  total  linear  shrinkage, 
plastic  basis,  is  21.0%  at  cone  11.  The  softening  point  is  cone  30.  The 
best  firing  range  is  from  cone  1  to  cone  11. 

No.  156  (p.  151).  Placer  County.  Lincoln.  Gladding,  ^McBean  &  Co. 
"Fire-proofing  Clay."  Tins  is  a  plastic,  low-grade  buff-burning  fireclay 
that  is  used  in  various  bodies  to  increase  the  refractoriness  of  the  mix- 
ture. It  contains  8.4%  of  -f200-mesh  sand.  The  plasticity  is  good,  the 
di-y  strength  is  medium-high,  and  in  the  dried  condition,  it  possesses 
finger-nail  hardness,  is  fine-grained,  and  close-textured.  The  colors  are: 
dry,  17"d ;  wet,  17"b ;  cones  010  to  5>  ll'd ;  cones  7  and  9,  17'"d ;  cones 
11  and  13,  17'''b.  Steel  hardness  is  developed  at  cone  02.  Less  than 
10%  absorption  appears  at  cone  1.  The  fired  structure  is  sound  and 
stony.  Slight  blistering  appears  when  fired  under  neutral  or  reducing 
conditions  to  cone  11  and  13.  The  fired  surface  texture  is  slightly 
rough.  The  maximum  total  linear  shrinkage,  plastic  basis,  is  18.9%, 
at  cone  9.  The  softening  point  is  cone  28-29.  The  best  firing  range  is 
from  cone  02  to  cone  9. 

No.  204  (p.  151).  Calavera.s  County.  Valley  Springs.  California 
Pottery  Co.  "Blue  Plastic."  The  properties  of  this  clay  are  closely 
similar  to  those  of  No.  203,  in  class  14,  but  it  contains  less  iron,  which 
results  in  lighter  fired  tones,  and  in  greater  refractoriness.  It  contains 
1.0%,  of  +200-mesh  material.  The  colors  are:  dry,  17"d ;  wet,  17"b; 
cones  010  to  04,  9"d  ;  cones  02  to  7,  13"d ;  cone  9,  15"d.  The  total 
linear  shrinkage,  plastic  basis,  is  18.4%,  at  cones  11  and  13.  The  soft- 
ening point  is  cone  27.  This  is  an  excellent  clay  for  buff-burned  face 
brick  and  roofing  tile. 

No.  213  (p.  59).  Amador  County.  lone.  Eckland  pit.  This  is  a 
buflF-burning  clay  with  smooth  and  strong  ])lasticity,  and  medium-low 
dry  strength.  In  the  dried  condition  it  is  medium-hard,  fine-grained, 
and  close-textured.  The  residue  on  200-mesh  is  12.6%.  The  colors  are : 
dry,  13"d ;  wet,  15'' ;  cones  010  to  02,  ll'd ;  cones  1  to  7,  13"f ;  cones 
9  to  13,  17"d  ;  strongly  nu)ttled  with  iron  specks.  Steel  hardness  is 
developed  at  cone  3,  and  less  than  10%  absorption  at  cone  13.  The 
fired  structure  is  sound  and  stony,  except  at  cones  11  and  13,  when  a  few 
large  cracks  appear  in  the  fired  test  pieces.  The  surface  texture  is 
smooth  until  cone  9  is  reached,  when  the  reduction  of  the  non-plastic 
ferro-magnesian  minerals  causes  a  pitted  surface.  The  total  linear 
shrinkage,  plastic  basis,  at  cone  13,  is  22.1%.     The  softening  point  if 


;^00  DIVISION  Ol''  MINES  AND  MINING 

cone  31.  The  best  firing-  range  is  from  cone  3  to  cone  8.  The  clay  is 
suitable  for  face  brick  and  faience  tile  mixes,  and  could  be  used  in 
some  fire  brick  mixes. 

No.  229  (p.  174).  Riverside  County.  Alberhill.  L.  A.  B.  Co.  "No.  7 
Pit."  This  is  a  buff-burning  i)lastic  fireclay  that  is  suitable  for  face 
brick  or  fire  brick  manufacture.  There  is  slight  effervescence  in  hydro- 
chloric acid.  It  contains  0.8'/^  of  -|-20()-mesh  sand.  The  plasticity  is 
smooth  and  strong,  the  dry  strength  is  medium-low,  and  in  the  dried 
condition  it  is  medium-hard,  fine-grained  and  close-textured.  The 
colors  are :  dry,  9"d ;  wet,  7"b ;  cones  010  to  06,  5'f ;  cones  04  to  3,  5''f ; 
cones  5  to  9,  17"f ;  cones  11  and  13,  17"(1.  Steel  hardness  is  developed 
at  cone  1,  and  less  than  10'^{  absorption  at  cone  9.  The  fired  structure 
is  sound  and  stony,  and  the  surface  texture  is  smooth.  The  total  linear 
shrinkage,  plastic  basis,  at  cone  13,  is  20. 4'/^ .  Slight  bloating  appears 
at  cone  15.     The  softening  point  is  cone  32. 

No.  230  (p.  174).  Riverside  County.  Alberhill.  G.,  McB.  &  Co. 
East  Pit.  "No.  9  Clay."  This  is  a  buff -burning  refractory  clay  with 
smooth  and  strong  plasticity,  and  medium-high  dry  strength.  It  con- 
tains 2.0 9(  of  -|-200-mesh  sand.  In  tlie  dried  condition  it  is  medium- 
hard,  fine-grained,  and  close-textured.  The  colors  are :  dry,  13""d ; 
wet,  17""d;  cones  010  to  04,  pinkish  white;  cones  02  to  7,  yellowish 
white;  cones  9  and  11,  19"f ;  cone  13,  17'"d.  Steel  hardness  is  devel- 
oped at  cone  02,  and  less  than  10%  absorption  appears  below  cone  5. 
The  fired  structure  is  stony,  and  all  test  pieces  are  broken  into  two  or 
more  pieces  by  fracturing.  The  total  linear  shrinkage,  plastic  basis,  at 
cone  13,  17.5  %  •  The  softening  ])oiut  is  cone  32-33.  The  clay  can  not 
be  used  alone,  but  when  mixed  with  non-plastic  material,  it  is  an  excel- 
lent clay  for  face  brick,  fire  brick,  and  terra  cotta. 

No.  245  (p.  52).  Amador  County.  lone.  Core  drill  hole  No.  55-1. 
Arroyo  Seco  Grant.  This  is  a  buff-burning  clay  with  good,  but  sticky, 
plasticity  and  medium  dry  strength.  In  the  dried  condition  it  is  soft, 
friable,  fine-grained,  and  close-textured.  The  colors  are:  drv,  buff- 
Avhite;  wet,  17""f;  cone  1,  19"f;  cones  5  and  9,  17"d;  cone  13,  15"i. 
Steel  hardness  develops  below  cone  1,  and  less  than  10%  absorption 
between  cone  1  and  cone  5.  The  fired  structure  is  sound  and  stony,  and 
the  surface  texture  is  smooth.  The  total  linear  shrinkage,  plastic  basis, 
at  cone  13,  is  19.0%  .  The  softening  point  is  cone  30-31.  It  could  be 
used  in  face  brick,  terra  cotta,  tile,  and  fire  brick.    - 

iVo.  545  (p.  52).  Amador  County.  lone.  Core  drill  hole  No.  55-3, 
Arroyo  Seco  Grant.  The  plasticity  is  good,  but  sticky ;  the  dry 
strength  is  medium,  and  in  the  dried  condition  it  is  soft,  friable,  fine- 
grained, and  close-textured.  The  colors  are :  drv,  gravish  white ;  wet, 
15"'"f;  cones  1  and  5,  19"f;  cone  9,  17""f;  cone  13,  17""d.  Steel 
hardness  is  developed  below  cone  1,  and  less  than  10%)  absorption  is 
jiroduced  between  cone  1  and  cone  5.  The  fired  structure  is  sound  and 
stony,  and  the  surface  texture  is  smooth.  The  total  linear  shrinkage, 
plastic  basis,  at  cone  13,  is  16.7% .     The  softening  point  is  cone  29. 

No.  247  (p.  52).  Amador  County.  lone.  Core  drill  hole  No.  55-2, 
Arroyo  Seco  Grant.  This  is  similar  to  No.  246,  but  has  greater 
shrinkage,  a  higher  softening  point,  and  effervesces  slightly  in  hydro- 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  301 

chloric  acid.     Tin*  total  liiicai-  shrinkage,  plastic  basis,  at  cone  13,  is 
19.5Vc.    The  softenino:  point  is  cone  32. 

No.  2iS  (]).  52).  Amador  Connty.  lone,  ("ore  drill  hole  No.  56-1, 
Arroyo  Seeo  Grant.  Tlic  plasticity  is  good,  the  dry  strength  is 
medium  high,  and  in  the  dried  condition  it  is  medium-hard,  fine- 
grained, and  clo.se-textured.  A  ]>art  of  the  sample  consists  of  soft  grains 
of  partly  kaolijiized  matter  tluit  is  not  rendered  i)lastic  by  the  usual 
methods  of  preparation.  This  results  in  a  heterogeneous  structure. 
The  colors  are:  dry,  17'"f;  ^vet,  17"'d  ;  cones  1  and  5,  17"d;  cones  9 
and  13,  17""h.  Steel  hardness  is  developed  below  cone  1,  and  less  than 
lO'/r  absorption  appears  between  cone  1  and  cone  5.  Blistering  is 
noticeable  at  cone  13.  The  maximum  total  linear  slirinkage,  plastic 
basis,  is  21.1 /r,  at  cone  9.  The  softening  point  is  cone  30-31.  It  is 
suitable  for  the  manufacture  of  terra  cotta  and  tile,  but  is  not  suitable 
for  making  a  good  fire  brick. 

No.  249  {\).b2).  Amador  County,  lone.  Core  drill  hole  Xo.  56-2, 
Arroyo  Seco  Grant.  This  is  very  similar  to  No.  245,  and  does  not 
require  a  separate  description.  The  total  linear  shrinkage,  plastic 
basis,  is  18.2'/  at  cone  13.    The  softening  point  is  cone  30-31. 

iVo.  55c?  (p.  52).  Amador  County,  lone.  Core  drill  hole  No.  57-3, 
Arroyo  Seco  Grant.  This  is  similar  to  No.  136  (class  8)  and  240 
(class  4),  with  the  differences  as  noted.  There  is  slight  effervescence 
in  hydrochloric  acid.  The  colors  are:  dry,  pinkish  white;  wet,  yellow- 
ish white;  cone  1,  nearly  white;  cones  5  and  9,  19"f;  cone  13,  17"'b. 
Steel  hardness  and  less  than  10/r  absorption  are  developed  between 
cones  1  and  5.  Xo  firing  cracks  were  noted.  The  total  linear  shrinkage, 
plastic  basis,  is  21.5%,  at  cone  13.     The  softening  point  is  cone  31-32. 

No.  254  (p.  52).  Amador  County,  loiu'.  Core  drill  hole  X"o.  57-4. 
Arroyo  Seco  Grant.  Tliis  sample  contains  more  coloring  matter  and 
more  non-plastic  ferro-nuignesian  minerals  than  No.  253.  There  is 
slight  effervescence  in  hydrochloric  acid.  The  i)lasticity  is  good,  the 
dry  .strength  is  medium,  and  in  the  dried  condition  it  is  soft,  fine- 
grained, and  open-textured.  The  colors  are:  drv,  17"f;  wet,  17"'f; 
cone  1,  15"f ;  cone  5,  17"'d  ;  cone  9,  17""d  ;  cone  13,  17"'b.  Steel  hard- 
ness appears  below  cone  1,  and  less  than  10%  ab.sorption  is  developed 
between  cone  1  and  cone  5.  The  fired  structure  is  sound  and  stony, 
except  that  at  cone  13,  one  large  crack  developed  in  the  test  piece. 
Blistering  is  noted  at  cone  13.  The  maximum  total  linear  shrinkage, 
pla.stic  basis,  is  21.6' v,  at  cone  9.  The  softening  point  is  cone  31.  This 
is  a  suitable  clay  for  face  brick,  terra  cotta  and  tile. 

No.  271  (p.  163).  Riverside  Countv.  Alberhill.  Alberhill  Coal  & 
Clay  Co.  "Lower  Tunnel,  Hill  Blue."  See  also  No.  9  and  272  in  class 
6,  and  No.  274  in  this  class.  The  plasticity  of  No.  271  is  smooth  and 
strong,  the  dry  strength  is  medium-high,  and  in  the  dried  condition  it 
is  hard,  fine-grained,  and  close-textured.  It  contains  2.0%  of  -|-200- 
mesh  sand.  There  is  slight  effervescence  in  hydrochloric  acid.  The 
colors  are :  dry,  13""  f ;  wet,  5""f ;  cones  010  to  9,  17"f ;  cones  11  and  13, 
21""d.  Steel  hardness  is  developed  at  cone  1,  and  less  than  10% 
absorption  at  cone  5.  One  or  two  of  the  test  pieces  show  small  cracks, 
otherwise  the  fired  structure  is  sound  and  stony,  and  the  surface  texture 


302  DIVISION  OF  MINES  AND  MINING 

is  siuootli.     Tlie  total  linear  slirinka<?e,  plastic  basis,  is  11. H%,  at  eonc 
13.    The  softening  point  is  cone  31-32.    For  uses,  see  No.  n,  in  class  6. 

No.  27i  (p.  K;:}).  Hiv(M-si(l(>  ("(.imtv.  Albcrliill.  A.  ('.  &  ('.  Co. 
"Upper  Tunnel  Hill  Blue."  See  also  No.  9  and  272  in  class  6,  and  No. 
271  above.  No.  274  is  intermediate  between  No.  271  and  272  in  its 
content  of  sand  and  its  ceramic  properties.  The  dry  strength  is 
medium.  There  is  no  effervescence  in  hydrochloric  acid.  Tlie  sample 
contains  11.4%  of  -f-200-mesh  sand.  The  colors  are:  dry,  I'^'^f ;  wet, 
ir)'""b;  cones  010  to  06,  15"f ;  cones  04  to  9,  17"f ;  cones  11  and  13, 
17"d.  Steel  hardness  is  developed  at  cone  ;1,  and  le.ss  than  10%  absorp- 
tion at  cone  9.  The  fired  structure  is  sound,  sliglitly  heterogeneous,  and 
the  surface  is  slightly  rough.  The  total  linear  shrinkage,  plastic  basis, 
at  cone  13,  is  19.8%.  The  softening  point  is  cone  30.  Tliis  is  a  suitable 
clay  for  fire  brick,  face  briclv  and  terra  cotta. 

c.  Dense-Burning,  Less  Than  6  Per  Cent  Apparent  Porositv 

Between  Cones  5  and  10. 

8.  Medium  to  High  Strength. 

No.  121  (p.  53).  Amador  County,  lone.  Arroyo  Seco  Grant.  Jones 
Butte.  Leased  by  Stockton  Fire  Brick  Co.  "Unctuous  Clay."  The 
available  quantity  of  this  clay  is  insufficient  for  commercial  production, 
but  a  sample  was  tested  as  a  matter  of  general  interest.  It  has  a  smooth 
and  strong  plasticity,  medium  dry  strengtli,  and  in  the  dried  condition 
it  is  medium-hard,  fine-grained  and  close-textured.  The  colors  are  :  dry, 
nearly  white ;  wet,  21'"f ;  cones  010  to  06,  pinkish  white ;  cones  04  to  9, 
yellowish  white ;  cones  11  and  13,  I'^'^f .  Steel  hardness  is  developed  at 
cone  04.  Less  than  10.0%  absorption  appears  at  cone  5.  The  fired 
test  pieces  are  stony  below  cone  11,  and  glassy  at  cone  11  or  above. 
They  are  sound,  but  seriously  warped.  The  total  linear  shrinkage, 
pla.stic  basis,  at  cone  13,  is  25.6%.  The  softening  point  is  cone  33. 
The  clay  is  closely  similar  to  some  of  the  varieties  that  are  mined  at 
Lincoln,  Placer  County,  especially  No.  146,  post. 

No.  124  (p.  56).  Amador  County.  lone  (Carbondale).  Leased  by 
G.  A.  Starkweather.  "Yarn  No.  1."  This  is  a  piuk-and-cream  burning 
clay  with  smooth,  moderately-strong  plasticity  and  medium  dry  strength. 
It  contains  1.0%  of  +200-mesh  sand.  The  dried  condition  is  soft, 
"soapy,"  fine-grained  and  open-textured.  A  strong  tendency  to  warp 
and  to  laminate  was  noted.  Tlie  colors  are:  drv,  2V"i;  wet,  21''"d; 
cones  010  to  04,  9'f ;  cone  02,  17"f ;  cones  1  to  1,  17"d ;  cones  9  to  13, 
19"f.  Steel  hardness  is  developed  at  cone  1.  Less  than  10%  absorption 
appears  at  cone  3.  The  fired  structure  is  generally  sound,  but  a  few 
pieces  split  in  firing.  The  total  linear  shrinkage,  plastic  basis,  at  cone 
13,  is  20.8 7('-  The  softening  point  is  cone  32.  The  best  firing  range  is 
above  cone  1.  The  claj''  is  suitable  for  fire  brick,  terra  cotta,  stone- 
ware, etc. 

A'o.  i55  (p.  58).  Amador  County.  lone  (Clarksona).  N.  Clark  and 
Sons.  "Dosch."  This  clay  has  been  well  knoAvn  for  many  years  in 
the  pottery,  stoneware,  and  terra  cotta  industries.  It  contains  but  1.2% 
of  -j-200-mesli  sand.  It  is  smooth  and  has  strong  plasticity,  medium 
dry  strength,  and  in  the  dried  condition  it  is  medium-hard,  fine-grained, 


CLAY  RESOURCES  ANI>  ,  ifiRAMIC  INDUSTRY  303 

aiul  close-textured.  Tlie  colors  are:  dry,  yellowish  Avhite;  wet,  17"'f; 
eone  010,  17"f,  becomin}?  nearer  to  wiiite  with  increasinrr  firing  tem- 
l)erature.  approximating?  19"f  at  cone  3;  cones  11 -and  13  (flashed) 
17"'.  Steel  hardness  ai>pears  at  cone  1.  and  less  tlian  10','  absorption 
at  cone  3.  The  fired  structure  is  sound,  stony  and  smooth-textured. 
The  maxinmm  total  linear  shrinkage,  plastic  basis  is  21.0%  at  eone  13. 
Slio-ht  bloating  was  noted  at  cone  15.  The  softening  point  is  cone  31. 
The  l)est  firing  range  is  from  eone  1  to  eone  13.  Tlie  clay  can  be  ca.st 
and  jiggered. 

No.  lie  (p.  156).  Placer  County.  Lincoln.  Lincoln  (May  Products 
Co.  "Xo.  1-6."  This  is  the  best  known  variety  of  Lincoln  clay  at  the 
present  time.  It  is  shipped  to  all  parts  of  the  Pacific  Coast  for  use  iu 
stoneware,  pottery,  faience  tile,  terra  cotta,  fire  brick,  and  other  pur- 
poses. It  is  an  excellent  clay  for  casting  and  jiggering.  The  plasticity 
is  smooth  and  strong,  and  it  contains  but  0.6%  of  --f-200-mesh  sand.  The 
dry  strength  is  medium,  and  in  the  dried  condition  it  is  soft,  fine- 
grained and  close-textured,  with  a  talcv  feel.  The  colors  are :  dry, 
buff- white  ;  wet,  17''d ;  cones  010  to  04,  ll"f ;  cone  02,  13"f ;  cones  1  and 
3,  17"f;  cone  5,  17'f;  cones  7  and  9,  21"'f;  cone  11,  17""f;  cone  13, 
13""f.  Steel  hardness  is  developed  at  cone  1.  Less  than  10%  absorp- 
tion appears  at  cone  3,  and  vitrification  is  complete  at  cone  9.  Slight 
blistering  is  noticeable  on  test  pieces  fired  under  reducing  or  neutral 
conditions  at  cones  11  to  15.  The  fired  structure  is  sound  and  stony. 
The  maximum  total  linear  shrinkage,  plastic  basis,  is  21.5%,  at  cone  11. 
The  softening  point  is  cone  31-32.  The  best  firing  range  is  from  cone 
1  to  cone  11.  The  long  vitrification  range,  the  excellent  plasticity,  and 
the  ability  to  withstand  abuse  in  drying  and  firing,  are  the  important 
advantages  that  this  clay  possesses  to  a  greater  degree  than  any  other 
clay  in  the  state  that  is  available  in  commercial  quantities  to  the  entire 
iiulustry.     The  same  is  true  of  Xo.  280,  see  po!il. 

No.  147  (]).  156).  Placer  County.  Lincoln.  Lincoln  Clay  Products 
Co.  "Xo.  7."  This  clay  is  very  similar  to  Xo.  146,  but  fires  to  slightly 
darker  tones.  It  is  used  in  faience  tile,  face  brick,  and  sewer-pipe 
mixes,  but  is  not  quite  as  suitable  for  casting  and  jiggering  as  No.  146. 
The  colors  are:  drv,  9"d ;  wet,  13'"b;  cones  010  to  04,  5'f ;  cones  02  and 
1,  ll"f;  cone  3,  i5"f;  cone  5,  17"f;  cones  7  and  9,  17'"f;  cone  11, 
17""f;  cone  13,  13""d.  Steel  hardness  is  developed  at  cone  1,  and 
less  than  10%  absorption  is  developed  at  cone  3.  Vitrification  is  com- 
plete at  cone  9 — ,  and  blisfei-ing  is  well  develojied  at  cone  13.  The 
maximum  total  linear  shrinkage,  plastic  basis,  is  21.4%,  at  cone  11. 
The  softening  point  is  cone  31. 

No.  1.51  (p.  156).  Placei-  County.  Lincoln.  Lincoln  Clay  Products 
Co.  "Wa.shed  China  Clay. ' '  This  sample  was  supplied  by  Mr.  Dillman 
from  a  warehouse  stock  of  some  material  that  was  prepared  some  years 
ago  by  washing  the  Xo.  1-6  (sample  X'^o.  146)  clay,  in  an  attempt  to 
produce  a  china  clay  for  the  local  market.  The  color  was  improved 
slightly  by  this  treatment,  but  not  sufficiently  to  permit  the  use  of 
the  clay  as  a  substitute  for  English  china  clay,  and  the  shrinkage  was 
increased  greatly  beyond  the  already  high  shrinkage  of  the  crude  clay. 
Slight  blistering  appears  at  cone  11.  The  maximum  total  linear  shrink- 
age, plastic  basis,  is  25.6%,  at  cone  9.    The  softening  point  is  cone  30. 


^04  DIVISION  OF  MINES  AND  MINING 

There  is  slifi:lit  effervescence  in  liydrochloric  acid.  Sfuiniiiiii^-  was  not 
noticed,  as  in  the  majority  of  the  crude  Lincoln  and  lone  clays,  but  no 
special  tests  Avere-inade  to  determine  if  washing?  iuid  completely  removed 
the  vaiuidium  salts  which  have  been  stated  to  be  the  cause  of  scumming 
of  these  clays/ 

No.  152  (p.  147).  Placer  County.  Lincoln.  Clay  Corporation  of  Cali- 
fornia. This  samjile  of  plastic  fire  clay,  toji'cther  with  Xo.  15:}  (class 
7),  was  taken  from  the  i)it  a])pi-oach  durinf>'  the  i)relimiiuiry  develop- 
ment of  this  ])roperty.  Tlie  test  results  should  be  comi)ared  with  those 
of  Xo.  280,  which  sample  was  sui)plied  by  the  company  from  the  ware- 
house after  full-scale  production  had  been  i-eached.  Xo.  152  has  excel- 
lent plasticity,  medium-hijih  dry  streno'th,  and  in  tlie  dried  condition  it 
is  soft,  fine-<irained,  and  oi)en-textured.  It  contains  23.6';,  of  -|-2()0- 
mesh  saiul.  The  colors  are:  dry,  nearly  white,  wet,  17"'f;  cones  010 
to  02,  i)inkish  white;  cones  1  to  7,  17'f;  cones  9  to  13,  17"'f.  Steel 
hardness  ap])ears  at  cone  1.  Less  than  lO' ,'  absorption  is  developed  at 
cone  1.  Slight  blistering  is  a])])arent  at  cone  13.  The  fired  structure 
is  stony,  and  most  of  the  fired  test  ])ieces  contain  one  or  more  large 
cracks,  some  of  which  cause  rujiture  of  the  test  piece  into  two  or  more 
fragments.  The  maximum  total  linear  shrinkage,  plastic  basis,  is 
26.4',y ,  at  cone  11.  The  softening  jjoint  is  cone  33.  It  was  stated  by 
the  comjiany  that  as  a  rule  the  softening  ])oint  of  this  clay  is  below  cone 
29,  so  that  the  sample  obtained  for  testing  may  not  be  re]U'esentative. 

No.  157  (p.  151).  Placer  County.  Lincoln.  Gladding,  :\IcBean  &  Co. 
"Terra  Cotta  Clay."  This  corresponds  to  Xo.  146,  and  is  used  as  the 
basis  for  terra  cotta  and  faience  tile  body  mixes.  It  contains  2.2%  of 
-f-200-mesh  sand.  The  plasticity  is  (>xcellent,  the  dry  strength  is 
medium,  and  in  the  dried  condition  it  is  medium-hard,  fine-grained,  and 
close-textured.  The  colors  are:  drv,  17"f;  wet,  17"d;  cones  010  to  1, 
ll"f;  cones  3  to  9,  17"d;  cones  11  and  13,  17""d  (flashed).  Steel 
hardness  is  developed  at  cone  04.  and  less  than  10*;,  absor])tion  apjiears 
at  cone  3.  The  fired  structure  is  sound  and  stony,  excei)t  that  a  few 
small  cracks  ai)peared  in  some  test  j)ieces  during  firing.  The  fired  sur- 
face texture  is  smooth.  Slight  blistering  is  noticeable  at  cone  13.  The 
maximum  total  lineai-  shrinkage,  plastic  basis,  is  23.6%,  at  cone  13. 
The  softening  point  is  cone  32-33. 

No.  175  (p.  65).  Butte  County.  Oroville.  Table  ^Mountain  Clay 
Products  Co.  This  is  a  plastic,  buff-burning  clay  from  the  lone  fornui- 
tion.  The  plasticity  is  smooth  and  strong,  the  dry  strength  is  nu'dium, 
and  in  the  dried  condition  it  is  soft,  "talcy, "  fine-grained,  and  close- 
textured.  It  contains  2.4^,  of  -|-200-mesh  sand.  The  colors  are:  drv, 
]7"f ;  wet,  15"d;  cones  010  to  04,  7'f ;  cone  02,  ll'f ;  cones  1  to  5,  15'd; 
cones  7  and  9,  15"d ;  cones  11  and  13,  17"'b.  Steel  hardness  is  devel- 
oped at  cone  02,  aiu1  less  than  10*^,'  absorption  at  coiu'  1.  The  fired 
structure  is  stony,  and  the  surface  texture  is  exceptionally  smooth.  Up 
to  cone  7,  all  test  pieces  are  sound,  and  at  cone  7  and  above,  each  test 
piece  is  fractured  into  two  or  more  fragments.  The  total  linear  shrink- 
age, i)lastic  basis,  at  cone  13,  is  IS. 9'^  .  Bloating  is  ]ironounced  at  cone 
15.      The  softening  point  is  cone  30-31.     The  best  firing  range  is  from 

'See  Currv,  E.  R.,  Notes  on  Green  Scummins:  .Tour.  Am.  Cer.  Soc,  Vol  9,  p.  .^92, 
192G. 


(LAY  RESOURCES  AXD  CERA^flC  INDUSTRY  305 

cone  02  to  I'onc  l:?.  Since  tlie  sainplc  was  taken  near  the  surface  durinf; 
tlic  |)reliniinary  developnieiit  of  the  i)roi)ertY.  it  may  not  be  representa- 
tive. The  clay  is  suitahh>  foi-  the  manufacture  of  fire  bi-ick,  roofing-  tih', 
terra  cotta,  and  for  any  pottery  oi-  decorative  tih'  in  whicli  the  l)ulf  color 
is  not  objectionabh". 

No.  201  (p.  69).  Calaveras  Count \.  llelisma.  This  is  a  plastic, 
buft'-burning  clay  from  the  lone  formation.  The  plasticity  is  smooth 
and  strong,  the  dry  strength  is  high,  and  in  the  dried  condition  it  has 
finger-iuiil  hardness,  is  fine-grained,  antl  close-textured.  The  sample 
contains  11.4'/^  of  +200-mesh  sand.  Tiie  colors  are:  dry,  17'"f;  wet, 
17"'f ;  cones  010  to  04,  ll"i;  cones  02  and  1,  17''d;  cones  3  to  6,  17"b ; 
cones  9  to  13,  17'".  Steel  hardness  and  lO'^  absorption  are  developed 
at  cone  04.  The  fired  structure  is  tough,  stony  aiul  .sound,  excei^t  at 
cones  11  and  13,  where  large  cracks  appear.  Vitrification  is  complete  at 
cone  9,  above  which  temperature  bloatnig  begins,  but  the  softening  point 
is  cone  28.  The  maximum  total  linear  shrinkage,  plastic  basis,  is  21.5% 
at  cone  9.     The  clay  is  suitable  for  the  uuniufacture  of  face  brick. 

No.  252  {\i.  y)2).  Amador  County,  lone.  Core  drill  hole  No.  57-2, 
Arroyo  Seco  Grant.  Tliis  sample  i.s  similar  to  No.  245  and  249,  in 
class  7,  with  the  important  diiil'erences  as  noted  below.  The  colors  are: 
dry,  17"f ;  wet,  17"'f ;  cone  1,  13"f ;  cone  5,  17"'f ;  cone  9,  17'"d ;  cone 
13,  17""d.  Slight  blistering  is  noted  at  cone  13.  The  maximum  total 
linear  shrinkage,  plastic  basis,  is  22.4%,  at  cone  9.  The  softening  point 
is  cone  32-33. 

Ao.  ^80  (p.  147).  Placer  County.  Lincoln.  Clay  Corporation  of  Cali- 
fornia. See  also  No.  153  and  146.  The  plasticity  is  excellent,  the  dry 
strength  is  medium-high,  and  in  the  dried  condition  it  is  medium-hard, 
close-grained,  and  fine-textured  The  bonding  strength,  with  50% 
(3ttawa  sand  from  — 20  to  +30-mesh,  is  211  lb.  per  sq.  in.  It  con- 
tains 11.2%  of  +200-mesh  sand.  There  is  slight  effervescence  in 
hvdrochloric  acid.  The  colors  are:  dry,  nearly  white;  wet,  17"'f ;  cones 
010  to  04,  7'f ;  cones  2  to  5,  7"f ;  cones  7  to  13,  21""d.  Steel  hardness 
is  developed  at  cone  02,  and  less  than  10%  absorption  at  cone  1.  The 
fired  structure  is  stony,  and  is  sound  up  to  cone  9.  At  cones  11  and 
13,  a  few  cracks  are  noted,  and  there  is  slight  blistering.  The  surface 
texture  is  smooth.  The  maximum  total  lineai'  shrinkage,  plastic  basis, 
is  20.3%,  at  cone  9.  The  softening  point  is  cone  30-31.  The  clay  is 
used  by  the  Stockton  Fire  Brick  Co.  in  the  manufacture  of  fire  brick 
and  refractory  cement,  aiul  is  marketed  to  tile  manufacturers  and 
others. 


20—54979 


306 


DIVISION  OF  MINES  AND  MINING 


TABLE    No.  20. 

II.    Buff-Burning    Clays. 

A.   Refi'actory  clays,  softi'iiing  point  cone  27  +  . 

b.   Dense-burning,   less  than   6''/<    apparent  porosity  between  cones   10   and   15. 

7.  Mainly  medium  to   high  strength,   but  also   including  some  clays  of  low  strength. 


Clay 

No. 

%  S.W. 

%  P.w. 

1.3 

12.4 

15.9 

3!t 

14.7 

18.1 

.■iC 

13.1 

10.9 

8U 

17.0 

24.8 

83 

12.8 

17.5 

85 

16.3 

17.7 

101 

16.5 

17.1 

110 

20.3 

20.6 

i:{;i 

22.4 

21.5 

149 

18.6 

18.8 

15.3 

20.7 

21.8 

156 

20.3 

17.1 

204 

17.1 

17.7 

213 

15.5 

23.8 

229 

17.0 

18.4 

230 

15.4 

18.4 

245 

19.6 

17.2 

246 

15.2 

17.2 

247 

18.1 

20.7 

248 

27.3 

16.4 

249 

18.7 

16.8 

253 

20.2 

20.5 

254 

19.6 

21.8 

271 

17.0 

17.5 

274 

19.1 

15.4 

%  W.P. 
28.3 
32.8 
24.0 
41.8 
30.3 
3  4.0 
33.6 
40.9 
47.9 
37.4 
42.5 
37.4 
34.8 
39.3 
35.4 
33.8 
36.8 
32.4 
38.8 
43.7 
35.5 
40.7 
41.4 
34.5 
34.5 


D.T.S. 
255 
257 
628 
Erratic 
230* 
245 
355 

200-400 
140 
260 
616 
670 
280 
105 
181 
±419 

O  O  r 
o  o  O 

328 

309 
±680 
±395 

204 
±251 

531 

444 


%  D.V.S. 
22.4 
25.5 
26.4 
27.1 
22.8 
28.6 
30.0 
34.2 
34.6 
32.5 
33.7 
36.1 
29.9 
24.7 
29.7 
27.4 
34.5 
26.8 
30.4 
48.4 
33.8 
33.3 
32.2 
30.4 
35.1 


%  D.L.S. 


7 

7 
8 
8 
7, 
8 
9 
10 
10.4 
9.8 
10.2 
10.8 
9.1 
7.6 
9.1 
8.3 
10.4 
8.2 
9.2 
14.1 
10.2 
10.1 
9.7 
9.2 
13.4 


Soften- 
ing pt. 
in  cones 
29-30 
29 
27 
33 
29 

31-32 
30 

32-33 
33 

31-32 
30 

28-29 
27 
31 
32 

32-33 
30-31 
29 
32 

30-31 
30-31 
31-32 
31 

31-32 
30 


*  Bonding  strength  with  50%  Ottawa  sand   ( — 20-  +  30-mesh)   is  56  lb.  per  sq.  in. 


c.  Dense-burning,  less  than  6%  apparent  porosity  between  cones  5  and  10. 


8.   Medium  to  high  strength. 


Clay 
No. 
121 
124 
136 
146 
1^7 
1^1 
152 
157 
175 
201 
252 
280 


;  S.W. 
27.4 
17.4 
20.9 
19.7 
20.5 
29.5 
26.8 
20.2 
15.4 
23.2 
17.6 
19.5 


%  P.W 
20. 
19. 
20. 
19. 
U 
28. 
22. 
22. 
17. 
18. 
21.1 
20.7 


%  W.P. 
48.1 
37.0 
41.0 
38.8 
39.2 
37.9 
49.4 
42.3 
.'!2.5 
41.4 
38. 7 
40.2 


D.T.S. 

3  40 
219 
270 
239 
284 
301 
710 
37!t 
369 
89  4 
296 
466* 


%  D.V.S. 
45.3 
29.4 
35.4 
34.0 
35.6 
43.4 
43.0 
33.2 
27.5 
40.2 
29.2 
33.1 


%  D.L.S. 
13.2 

8.9 
10.6 
10.3 
10.7 
12.8 
12.8 
10.1 

8.3 
11.9 

8.9 
10.0 


Soften- 
ing pt. 
in  cones 
33 
32 
31 

31-32 
31 
30 
33 

32-33 
30-31 
28 

32-33 
30-31 


•  Bonding  strength  with  50%  Ottawa  sand   ( — 20-  -f  30-mesh)  is  211  lb.  per  sq.  in. 

f/c  S.W.  =  Per  cent  shrinkage  water. 

%  P.W.  =  Per  cent  pore   water. 

f/r/W.P  =  Per  cent  water  of  plasticity. 

D.T.S  =  Dry  transverse  strength,  pounds  per  square  inch,   without  sand. 

%  D.V.S.  =  Drying  shrinkage,  per  cent  dry  volume. 

%  D.L.S.  =  Calculated   linear  drying  shrinkage,   per  cent  dry   length. 


CLAY  RESOURCES  AND  CERAl^fTC  TXDUPTRY 


307 


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308 


DIVISION  OF  !\nNES  AND  MINING 


A  lisc)i-]il  idii  ami   linear  .shi'iiikagc  cui'vcs  for  clays  of  class 


010  08  06  O^OZ  I    3  S    7    9  II   15  15- 


S 
I 

tt: 

S 

-J 
»^ 

•« 

^" 

I 

I 

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20 
10 
0 
20 
10 

o 

20 
10 
0 
20 
10 
0 


No 

13 

N 

^ 

— 

-^ 

—  • 

_s 

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-- 

-- 

-- 

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.A 

No 

39 

V 

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A. 

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^ 

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ft: 


//fAT  TREATneNTlNCOfiES. 


CIO  Oaob  Cf  OZ  I    3   S    7    S  II   13  IS" 

20 
10 
0 

20 
10 

o 

20 
10 
0 
20 
10 

HEAT  TRFATHFNT  IN  CONES 


_ 

No, 

83 

\ 

-^ 

»** 

— 

.. 

_s 

^^ 

— 

-^ 

A 

No 

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HEAT  TREATMENT  IN  CONES. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


309 


Absorption  and  linear  shrinkase  curves  for  clays  of  class  7. 
010  08  06  Of  OZ  I    3  5    7    S   II   13  ir 


HEfiCT  JREfirnENT  INC0NE5. 


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DIVISION  OP  MINES  AND  MINING 


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SI^VffXW'39^MNmSDNIilU  mSHllX   I'M NO/ldmSQn 


(LAY  RESOI'RCES  AND  fERA:viir  IXDITSTKY  ''ill 

ll-B.   Non-refractory   Clays,  Softening    Point  Cone  27 — . 

a.  Oi'E.\-HrKxix(;.   Xor   liKLow   6'/(    Aim'Akkxt   Porositv   P.elow 

Cone  10. 

9.  INIedium  to  IIii>:li  Streiij^th. 

Xo.  19  (p.  16:1).  Kiversidp  (\)nnty.  Albcrliill  V.  &  V.  Co.  "Yellow 
Strippin<ir. "  This  is  a  yello-\visli,  saiuly  (.'lay  that  occurs  as  overburden 
on  parts  of  the  i)roi)('rty.  It  contains  28.2%  of  --|-200-mesh  sand,  and 
has  sufficient  plasticity  and  stren<>th  to  i)enuit  its  use  in  a  superior 
grade  of  coiiunon  l)i-ick,  which  is  marketed  undei-  the  name  of  "Diamond 
Brand."  The  dry  stivngth  is  medin)u-lii<ih,  and  the  dried  clay  is  hard, 
■with  a  medium  j^rain  and  oi)en  te.xture.  The  colors  are:  dry,  15''d; 
wet,  15";  cones  010  to  cone  M,  7'd ;  cone  5,  9'f ;  cones  7  to  9,  ll'f ;  cone 
11,  15'f ;  and  cone  1-3,  15'b.  Fin<?er-nail  hardness  develops  below  cone 
010,  and  steel  liardness  at  cone  11.  A  few  small  craclvs  developed  in 
the  test  piece  that  was  fired  to  cone  13,  but  all  other  test  pieces  were 
sound.  The  total  linear  shrinka<2:e,  jilastic  basis,  is  8.4%,  at  cone  13. 
The  softenin<r  ])oint  is  cone  23.  The  best  firin<r  ranji-e  is  from  cone  010 
to  cone  11.  Tlie  clay  seems  entirely  suited  for  makinp;  bufP  and  pink 
face  brick.  It  does  not  vitrify  at  sufficiently  low  temjieratures  to  be 
suitable  as  the  sole  in<;redient  of  bodies  with  low  porosity. 

No.  25  ()).  163).  Riverside  County.  Alberhill  C.  k  C.  Co.  "West 
Tunnel  Blue."  See  No.  94  and  9.").  This  is  a  pink  and  butf -burning 
sewer-])ipe  clay  having  a  fail-  plasticity  and  medium  dry  strength.  It 
contains  18.8%  of  +200-mesh  sand.  In  the  dry  state  it  luis  a  medium 
grain  and  open  texture.  The  colors  are:  dry,  23'''''f;  wet,  23"'"d ; 
cones  010  to  04,  17"f ;  cones  02  to  5,  15''d  ;  cones  7  to  11,  15''b;  cone  13, 
Ty"".  It  is  practically  red-burning  at  cone  13,  but  is  best  classed  as  a 
buff-burning  clay.  Finger-nail  hai-dness  is  developed  at  cone  010,  and 
steel  hardness  at  cone  1.  Vitrification  is  well  advanced  at  cone  9.  The 
total  linear  shrinkage,  plastic  basis,  at  cone  13,  is  19.3%.  The  softening 
point  is  cone  16.  The  best  firiiig  range  is  from  cone  1  to  cone  13.  The 
])rincii)al  value  of  this  clay  lies  in  its  vitrification  i-ange  and  tempera- 
ture, coupled  with  good  fired  strength. 

No.  36  (p.  20).  San  Diego  County.  Card  iff.  California  Clay 
Products  Co.  This  is  a  Pleistocene  ( ?)  fireclay,  similar  to  samples  No.  33 
and  34  in  class  6,  but  with  less  iron  and  a  higher  percentage  of  fluxes, 
]irobably  feldspars.  It  contains  44.4%  of  -|-200-mesh  sand.  The 
l)lasticity,  and  the  dry  and  fii-ed  properties  are  closer  to  sample  No.  33 
than  to  No.  34,  but  the  colors  are  uniformly  of  lighter  tones  and  the 
fired  porosities  are  greater,  though  the  shriid^age  is  practically  the 
same.  The  total  linear  shrinkage,  ])lastic  basis,  at  cone  13,  is  8.2%. 
The  softening  point  is  cone  26.  The  best  firing  range  is  from  cone  1  to 
over  cone  13. 

No.  !H  (ni<]  !>.')  (\).  M\).  Kivcrside  {'()iint\.  Alberhill.  (1..  McB.  & 
Co.  No.  94  is  the  "West  Blue"  and  No.  95  is  the  "Select  West  Blue" 
clav.  These  two  samples  should  be  compare(_l  with  No.  25,  the  "West 
Tunnel  Blue"  of  the  Alberhill  C.  &  C.  Co.,  and  not  with  their  "West 
Blue"  (No.  23,  class  5)  and  "Select  West  Blue"  (No.  16,  class  10) 
varieties.     No  important  differences  betAveen  No.  94  and  95  were  dis- 


312  DR'^ISION  OF  MINES  AXD  MIXIXO 

closed  by  the  testiiifr,  but  they  both  have  a  hipher  proportion  of  sand 
and  a  lower  percentage  of  iron  than  No.  25,  Avhicli  results  in  a  largre 
difference  in  the  ceramic  properties  and  uses  of  No.  9-t  and  95,  com])ared 
with  No.  25.  No.  94  contains  24.2^f,  and  No.  95  contains  27.6'/;  of 
+200-niesh  sand,  compared  to  18.8'/f  for  No.  25.  The  plasticity  of 
No.  94  and  95  is  good,  the  dry  strength  is  medium,  and  in  the  dried 
state  they  are  soft,  medium-grained  and  open-textured.  The  colors 
are:  dr^',  17""f ;  wet,  neutral  gray;  cones  010  to  02,  l."]'"d;  cones  1  to 
13,  13""d.  Abundant  jiarticles  of  ferro-magnesian  minerals  give  a 
pleasing  granitic  texture  to  the  test  pieces  fired  above  cone  1.  Finger- 
nail hardness  ai)]iears  below  cone  010.  and  steel  hardness  at  cone  1. 
Absorptions  under  10*^^  are  obtained  at  cone  3.  Bloating  is  pronounced 
at  cone  11,  especially  when  a  reducing  flame  is  used.  No.  95  has  lower 
shrinkage  and  lower  absorption  at  cone  9  than  No.  94.  The  maximum 
total  linear  shrinkage,  plastic  basis,  is  at  cone  9.  and  is  11.7/^  for  No. 
94,  and  10.5 'y  for  No.  95.  The  softening  points  are  cones  17  and  18, 
respectively.  The  best  firing  range  is  from  cone  1  to  cone  9.  No.  94  is 
used  in  tile  bodies,  and  No.  95  in  terra  cotta  bodies. 

Ao.  5.9  (p.  171).  Riverside  County.  G.,  McB.  &  Co.  "Tile  Clay." 
This  is  a  red  and  tan-burning  plastic  clay  that  is  used  for  the  manu- 
facture of  roofing  tile,  face  brick,  and  similar  products.  There  is  slight 
effervescence  in  hydrochloric  acid.  It  contains  30.89c  of  -)-200-mesh 
quartz-mica  sand.  The  plasticity  is  excellent,  the  dry  strength  is 
medium  high,  and  in  the  dried  condition  it  is  medium  hard,  medium- 
grained,  and  open-textured.  The  colors  are:  dry,  13""d;  wet,  17""; 
cones  010  to  02,  7"b ;  cone  1,  ll"b;  cones  3  to  11,  13"b;  cone  13,  15". 
Mottling  from  the  presence  of  ferro-magnesian  minerals  is  pronounced 
above  cone  5,  giving  pleasing  textural  effects.  Finger-nail  hardness  is 
developed  below  cone  010,  and  steel  hardness  develops  at  cone  5. 
Absorjitions  below  107c  are  not  obtained  until  cone  11  is  reached. 
The  fired  structure  is  sound  and  stony  and  the  texture  is  rough.  The 
total  linear  shrinkage,  plastic  basis,  at  cone  13,  is  11.99^ .  The  softening 
point  is  cone  26-27.    The  best  firing  range  is  from  cone  02  to  cone  9. 

No.  114  (p.  90).  San  Bernardino  County.  Near  Rosamond.  Titus 
deposit.  This  is  a  buff-burning  clay  with  fair  plasticity,  medium  dry 
strength,  and  a  medium  hard,  medium-grained,  dried  condition.  It 
has  not  been  produced  steadily,  but  tests  have  been  made  by  various 
clay  manufacturers.  The  colors  are:  dry,  grayish  white;  wet,  23"'"f; 
cones  010  to  3,  17"f ;  cones  5  to  9,  17'"f ;  cones  il  and  13,  grayi.sh  white. 
Finger-nail  hardness  is  developed  below  cone  010.  and  steel  hardness 
appears  at  cone  1.  The  fired  structure  is  sound,  homogeneous,  stony, 
and  without  warp.  The  surface  texture  is  slightly  rough.  Above  cone 
11,  scattered  iron  specks  become  noticeable.  Absorptions  below  10/^ 
are  obtained  at  cone  9.  The  total  linear  shrinkage,  plastic  basis,  is 
6.9%,  at  cone  13.  The  softening  point  is  cone  17-18.  The  clay  might 
be  useful  in  stoneware,  vitrified  floor  tile,  and  similar  mixtures, 
altliougii  for  the  highest  purposes,  wasiiing  would  be  necessary  to 
remove  the  non-plastic  coloring  impurities. 

No.  13'i  (p.  58).  Amador  County.  lone  (Clarksona).  N.  Clark  and 
Sons.  "Dosch  Stripping."  This  is  a  sandy  yellow-burning  clay  with 
good  plasticity  and  medium-high  dry  strength.      It  contains  18.0%  of 


CLAY  RESOURCES  AND  CERAMIC   INDUSTRY  ^H  Tj 

-|-2()()-HiP.sh  sand.  In  the  dried  condition  it  is  medinm  hard,  fine- 
•rraincd,  and  close-textured.  The  colors  are:  dry,  lo"d;  wet,  15"1) ; 
cones  010  to  f),  9"d  ;  cone  7,  19"b.  .Steel  hardness  (lev(dops  at  cone  02, 
and  less  than  109'  absorption  at  cone  >].  Tlie  fired  structure  is  sound, 
g:rannlar  and  roup^h-textured.  A  vesicular  structure  develops  above 
cone  7.  Tlie  maximuni  total  linear  shrinkaofe,  plastic  basis,  is  15.1% 
at  cone  7.     Tliis  niatci'ijd  is  used  in  sewer-])i])(»  mixes. 

Xo.  168  (p.  1;)6).  Nevada  County.  Cliica^o  Pai-k.  Beaser  Rancli. 
Til  is  is  a  pink-burninj;  clay  from  near  the  surface  of  an  undeveloped 
deposit.  The  plasticity  is  smooth,  but  weak,  the  dry  strengtli  is  medium, 
and  in  the  di-ied  condition  it  is  medium  hard,  fine-»rained,  and  close- 
textured.  The  colors  are:  dry,  17"'f;  wet,  17"'d:  cones  010  to  06, 
l.yf;  cones  04  and  02,  15'd;  cone  1,  Wh.  The  fired  colors  are  ochra- 
ceous  salmons  and  butTs,  which  are  unusual.  No  scumminf?  or  efflo- 
rescence was  noted.  Steel  hardness  is  develo])ed  at  cone  02.  The  fired 
structure  is  .sound,  aiul  stony,  and  the  surface  texture  is  exceptionally 
smooth.  The  total  linear  shrinka<>'e,  ])lastic  l)asis,  is  8.6%  at  cone  1. 
The  clay  could  be  used  locally  for  common. brick,  and  might  be  u.sed  to 
make  an  attractive,  though  unusual,  face  brick. 

No.  169  {]).  VAH).  Nevada  County.  Pearldale.  Sonntag  Ranch.  This 
is  a  buff-burning  clay  from  a  surface  exposure  of  an  undeveloped 
deposit.  The  plasticity  is  fairly  smooth  and  strong,  the  dry  strength 
is  medium,  and  in  the  dried  condition  it  is  soft,  medium  grained,  and 
open-textured.  The  colors  are:  drv,  17"f;  wet,  17"d ;  cones  010  and 
08,  ll'f;  cone  06,  i:rf ;  cones  04  and  02,  15'f ;  cones  1  to  5,  17'f ;  cone 
7.  17"d;  cones  9  to  18,  17"'b,  but  with  a  distinctly  mottled  appearance. 
Some  interesting  color  etTects  for  floor  tile  and  face  brick  can  be  pro- 
duced with  this  clay.  Steel  hardness  is  developed  at  cone  1.  Less  than 
10%  absorption  appears  at  cone  7.  Slight  bloating  is  apparent  from 
the  shrinkage  and  porosity  data  at  cones  11  and  13,  but  no  loss  of  shape 
was  noted.  The  fired  structure  is  sound  and  stony,  and  the  surface 
texture  is  slightly  rough.  The  maximum  total  linear  shrinkage,  plastic 
basis,  is  11.1/^ ,  at  cone  9.  The  softening  point  is  cone  19-20.  The  best 
firing  range  is  from  cone  1  to  cone  9. 

Xo.  173  ( )).  2;>r)).  Yuba  County.  Smartsville.  J.  P.  Dempsey  Ranch. 
Kaolin itic  material  from  a  copper  prospect  in  volcanic  rocks.  It  was 
not  possible  to  secure  a  sample  entirely  free  from  limonite.  The  plas- 
ticity is  fair,  the  dry  strengtli  is  medium,  and  in  the  dried  condition,  it 
has  finger-iuul  hardness,  is  medium  grained,  and  open-textured.  A 
high  percentage  of  non-pla,stic  matter  is  present.  The  colors  are:  dry, 
yellowish  wliite;  wet,  17'"f ;  cone  010,  7"b;  fading  progressively  with 
increasing  firing  temperatures  to  13'"d  at  cone  5.  Green  scumming  is 
pronounced.  Steel  hardness  is  developed  at  cone  04.  The  fired  struc- 
ture is  sound,  and  fine-granular,  except  at  cone  6,  where  light  super- 
ficial hair-cracks  appear.  The  surface  texture  is  slightly  rough.  The 
total  linear  shrinkage,  plastic  basis,  at  cone  9,  is  19.1%. 

Xo.  255  {\).  r)2).  Amador  County.  Tone.  Core  drill  hole  No.  57-5, 
Arroyo  Seco  CI  rant.  This  is  similar  to  No.  254  in  class  7,  but  fires  to 
darker  colors.  The  plasticity  is  good,  the  dry  strength  is  medium,  and 
in  the  dried  condition  it  is  medium  hard,  fine-grained  and  open- 
textured.   There  is  slight  effervescence  in  hvdrochloric  acid.    The  colors 


314  DIVISION  OF  MINES  AND  MINING 

are:  dry,  i)"d;  wet,  9"b;  cone  1,  9"d;  cone  5,  15"d ;  cone  9,  17"b;  cone 
18,  15"i.  Steel  hardness  is  developed  below  cone  1,  and  less  than  10% 
absorption  between  cone  1  and  cone  5.  The  fired  structure  is  sound  and 
stony,  and  the  surface  texture  is  smooth.  No  blistering  w^as  noted  at 
cone  13.  The  total  linear  shrinkage,  plastic  basis,  at  cone  13,  is  21.6%. 
The  softening  point  is  cone  26.  This  is  a  good  clay  for  face  brick, 
roofing  tile,  and  similar  products. 

No.  283-A  and  B  (p.  232).  Tulare  County.  Dueor.  W.  A.  Sears 
deposit.  See  also  No  284,  class  10,  and  285,  class  5  These  are  samples 
of  impure  kaolin,  aiul  have  fair  plasticity  and  medium  dry  strength. 
The  dry  condition  is  medium-liard,  fine-grained,  and  open-textured. 
The  colors  of  No.  283-A  are:  dry,  nearly  white;  wet,  15'f ;  cones  010 
to  3,  17"d;  cones  5  and  7.  17^1;' cone  9,'l5'd;  cones  11  and  13,  13'd. 
The  colors  of  No.  283-B  are:  drv,  gravish  white;  wet,  21""f;  cones 
010  to  02,  17""f;  cones  010  to  5,  21'"f;  cones  7  to  13,  17"d.  The 
colors  are  rather  disagreeable  yellowish  buffs,  and  are  irregular.  Yel- 
low scumming  is  very  pronounced.  Steel  hardness  is  not  developed 
up  to  cone  13,  the  upper  temperature  limit  studied.  The  fired  struc- 
ture is  sound,  and  there  is  no  evidence  of  vitrification  up  to  cone  13. 
The  total  linear  shrinkage,  ])lastic  basis,  at  cone  13,  is  10.7%  for  No. 
283-A,  and  9.7%,  for  No.  283-B.  The  softening  point  of  No.  283-A 
is  cone  26-27.  Further  studies  are  needed  before  the  possible  uses  of 
these  clays  can  be  predicted. 

10.  Low  Strength. 

No.  16  (p.WS).  Riverside  County.  Alberhill  C.  &  C.  Co.  ''Select 
West  Blue."  See  also  No.  23  in  class  5.  This  is  a  plastic,  buff-burning 
clay  that  has  a  wide  vitrification  range  above  cone  7,  and  is  used  for 
face  brick  and  pottery.  It  contains  22.6%  of  4-200-mesh  sand,  high 
in  ferro-magnesian  minerals,  which  results  in  a  pleasing  granitic  texture 
when  fired  above  cone  7.  The  plasticity  is  fair,  the  dry  strength  is  low, 
and  the  clav  is  soft  and  friable  in  tlie  dry  state.  The  colors  are :  drj^ 
15'""f ;  Avet,  15'""b ;  cones  010  to  02,  17''f ;  cones  1  to  5,  17'"f ;  cones 
7  to  13,  17""f,  with  a  granitic  texture.  Finger-nail  hardness  is 
developed  at  cone  06,  steel  hardness  at  cone  02,  and  bloating  begins  at 
cone  13.  The  total  maximum  linear  shrinkage,  plastic  basis,  is  14.0%, 
at  cone  11.  The  softening  point  is  cone  18.  The  best  firing  range  is 
from  cone  02  to  cone  11. 

No.  55  (p.  195).  San  Bernardino  County..  4.2  m.  N.E.  of  Bryman. 
Gladding,  McBean  and  Co.  This  is  a  vitrifying  clay  of  value  in 
face-brick  manufacture.  It  has  poor  plasticity,  low  dry  strength,  and  a 
soft,  oi)en,  dry  condition.  A  large  proportion  of  non-plastic  matter  is 
present  which  is  high  in  iron,  and  results  in  a  pleasing  granitic  texture 
when  fired.  The  ])ercentage  remaining  on  20()-m('sh  is  48.6.  The  colors 
are:  dry,  7"f ;  wet,  7"d ;  cones  010  to  04.  7"f,  cones  02  to  5,  9'"d  ;  cones 
7  to  11*,  17""d;  cone  13,  15""'(1.  Finger-nail  hardness  is  obtained 
below  cone  010,  and  steel  hardness  develops  at  cone  1.  Absori)tions 
below  10%  are  obtained  at  cone  3  oi-  above,  and  bloating  begins  above 
cone  11.  The  maximum  total  linear  shrinkage,  plastic  basis,  is  9.5%,  at 
cone  11.  The  softening  point  is  cone  18.  The  best  firing  range  is  from 
cone  02  to  cone  11. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  315 

No.  8:i  (p.  174).  Riverside  County.  Albeiiiill.  L.  A.  B.  Co.  "Clay 
Shale."  This  is  a  sandy,  buff-burning:  clay  shale,  with  weak  plasticity 
and  incdiuin  low  streu^Hi.  It  effei-vcsccs  sli<:li11y  in  liydroehloric  acid. 
In  the  dried  condition  it  is  soft,  medium-grained  and  open-textured. 
The  colors  are:  dry,  17''d;  wet,  17";  cones  010  to  3,  5'f ;  cones  5  to  11, 
5)'f;  cone  13.  17'f.  Troii  sjjecks  are  numerous.  Finger-nail  hardness 
develops  below  cone  010.  but  steel  hai-diiess  is  l)ar('ly  attained  at  cone  13, 
at  Avhicli  point  bloating  begins.  The  fired  structure  is  sound,  granular, 
and  open.  The  maximum  total  linear  firing  shrinkage,  plastic  basis,  is 
3.5%,  at  cone  11,  nearly  all  of  wiiich  takes  ])lace  during  drying.  The 
softening  i)oint  i.s  cone  23-20.  The  best  firing  range  is  from  cone  010  to 
cone  11.  The  clay  may  be  used  with  more  i)lastic  clays  as  an  ingredient 
of  face  brick  mixtures,  if  the  mottled  texture  is  not  objectionable. 

No.  88.  (Dei)osit  not  deseril)C(l.)  Riverside  County.  Hudson 
Ranch,  near  Elsinore.  Tliis  is  an  imi)ure  silica  sand,  mixed  with 
enough  clay  to  im])art  weak  plasticity  to  the  mass.  The  dry  strength  is 
medium  low,  and  in  the  dried  condition  it  i.s  coarse,  open,  and  friable. 
The  colors  are:  dry,  21""f ;  wet,  17""f ;  fired,  from  cone  010  to  cone  11, 
grayish-white,  with  black  specks  above  cone  7.  Steel  hardness  is  devel- 
oped at  c(me  11.  The  fired  structure  is  coarse-grained,  and  weak. 
Enough  fluxes  are  present  to  cause  fusion  to  begin  at  cone  9.  The  total 
linear  shrinkage,  plastic  basis,  at  cone  9,  is  8.3%.  The  material  has 
little  ceramic  value. 

No.  Ill  (p.  178).  Riverside  County.  Alberliiil.  P.  C.  P.  Co.  "Lower 
Douglas."  This  is  a  pink-burning  clay  containing  28.6%  of  +200- 
mesh  sand,  but  nevertheless  i)()ssessing  good  jilasticity,  and  a  medium 
low  dry  strength.  The  dried  condition  is  soft,  medium-grained,  and 
open-textured.  The  colors  are:  drv,  17"f;  wet,  15"d;  cones  010  to  1, 
9"f ;  cone  3,  15"  f ;  cones  5  to  9,  13'"f ;  cones  11  and  13,  17""f .  Above 
cone  5.  the  clay  is  strongly  mottled  with  iron  specks,  resulting  in  a 
pleasing  fine-granitic  texture.  Finger-nail  hardness  appears  below 
cone  010,  and  steel  hardness  at  cone  1.  The  fired  structure  is  sound  and 
fine-granular.  Slight  bloating  begins  at  cone  11.  Absori)tions  below 
10%  are  obtained  at  cone  5  or  above.  The  maximum  total  linear  shrink- 
age, plastic  basis,  is  12.4%,  at  cone  9.  The  softejiing  point  is  cone 
19-20.  The  clay  is  useful  in  terra  cotta,  face  brick,  and  faience  tile 
bodies. 

No.  167  (p.  ISA).  Nevada  County.  Wolf.  Coe  property.  Pine  Hill 
:\rine.  See  also  Xo.  159  and  160  in  class  1,  and  166  in  class  11.  This  is 
similar  to  No.  160,  but  contains  more  iron.  The  plasticity  is  weak,  the 
dry  strength  is  low,  and  in  the  dried  condition  it  is  soft,  fragile,  fine- 
grained, and  open-textured.  The  colors  are:  dry,  7"b ;  wet,  9'b;  cones 
010  to  3,  7"b;  cones  5  to  9,  7"d ;  cones  11  and  13,  17"'d.  Finger-nail 
liardness  is  developed  at  cone  010,  and  steel  hardness  at  cone  11.  Less 
than  10%  absorption  is  obtained  at  cone  13.  The  fired  structure  is 
sound,  and  below  cone  11,  is  fine-granulai".  Above  cone  11,  it  is  stony. 
The  total  linear  shrinkagf.  ])laslic  basis,  at  eone  13,  is  13.6^1,.  The 
sofi cuing  [>oiut  is  cone  23. 

No.  170  (p.  136).  Nevada  County.  Banner  Mountain  road.  This  is 
an  impure,  sandy,  i)ink-])urning  clay  with  weak  plasticity,  and  medium- 
low  dry  strength.      In  the  dried  condition  it  is  medium-hard,  coarse- 


316  DIVISION  OF  MINES  AND  MINING 

grained,  and  open-textured.  The  colors  are:  dry,  17"d  ;  wet,  17"  b; 
cones  010  to  06,  13"b ;  cones  04  to  1,  13"d.  Steel  hardnes.s  is  develoi)ed 
at  cone  02.  The  fired  structure  is  sound,  granular,  open-textured,  and 
the  surface  texture  is  smootli.  Tlie  total  linear  shrinkage.  ])lastic  basis, 
is  4.8%,  at  cone  3.  It  could  be  used  for  common  brick,  but  the  plasticity 
is  barel.y  sufificient. 

No.  238  (p.  70).  Calaveras  County.  Campo  Seco.  This  is  an  nnpure 
sericite  schist  that  is  said  to  have  been  used  as  a  refractory  clay  in  the 
former  smelter  of  the  Penn  Mining  Co.  The  jilasticity  is  weak,  the  dry 
strength  is  low,  and  in  the  dried  condition  it  is  very  soft  and  friable. 
The  colors  are :  dry  and  wet,  grayish  white ;  cone  010,  17"f ;  cones  06 
to  1,  17"d ;  cones  5  and  9,  2V'"i.  Steel  hardness  is  developed  at  cone 
02,  and  less  than  10%  absorption  at  cone  5.  A  vesicular  structure 
developed  at  cone  9.  The  maximum  total  linear  shrinkage,  ])lastic 
basis,  is  9.3%,  at  cone  5.     The  material  is  of  doubtful  value  in  ceramics. 

No.  269.  Inyo  County.  American  Silica  Co.  "Death  Valley  Super- 
fine." This  is  a  very  fine-grained,  sandy  material,  with  sufficient  clay 
to  give  a  short  and  s])ongy  plasticity  to  the  nuiss.  There  is  con- 
siderable effervescence  in  hydrochloric  acid.  The  dry  strength  is 
medium  Ioav,  and  in  the  dried  condition  it  is  hard,  and  has  a  fine  sandy 
texture.  The  colors  are  :  dry,  17'"d  ;  wet,  17'"b ;  cones  010  to  06,  15"f ; 
cones  04  to  1,  whiter  than  17";  cone  3,  17"d.  Steel  hardness  is  devel- 
oi)ed  at  cone  3.  The  fired  structure  is  sound  and  fine-granular.  The 
total  linear  shrinkage,  plastic  basis,  is  26.6%,  at  cone  3.  The  softening 
point  w^as  not  determined. 

No.  284  (p.  232).  Tulare  County.  Ducor.  W.  A.  Sears  deposit. 
See  also  No.  285,  class  5.  and  283-A  and  B.  class  9.  This  is  an  impure 
kaolin,  having  weak  plasticity,  low  dry  strength,  and  a  medium-hard, 
coarse-grained,  open  texture  in  the  dry  condition.  It  was  only  fired  to 
four  cone  numbers.  The  colors  are:  dry,  15"d;  wet,  17";  cones  1,  5,  9 
and  13,  15".  The  fired  colors  are  rather  unsatisfactory  yellows  for 
most  ceramic  jiroducts.  The  fired  structure  is  weak  and  coarse-granu- 
lar. The  total  linear  shrinkage,  plastic  basis,  is  6.4%.  The  softening 
point  was  not  determined.  This  is  the  least  satisfactory  of  the  sam- 
ples tested  from  this  de])osit.     Yellow  scumming  is  jironounced. 

b.  Dense-Burning,  Less  Than  6%    Apparp:nt   Porosity  Below 

Cone  10. 

11.  Low  Strength. 

No.  166  (p.  rm.  Nevada  County.  Wolf.  Coe  property.  Pine  Hill 
Mine.  See  also  No.  159  and  160  in  class  1  and  167  in  class  10.  This  is 
similar  to  No.  159,  but  contains  a  higher  jiroportion  of  fluxes  and  color- 
ing matter.  The  residue  on  200-mesh  is  4.6%.  The  plasticity  is  smooth, 
and  moderately  strong,  the  dry  strength  is  medium-low,  and  in  the  dried 
condition  it  is  medium-hard,  fine-grained  and  close-textured.  The 
colors  are  :  dry,  13"f ;  wet,  9"d  ;  cones  010  to  06,  7"f ;  cones  04  to  3,  5"f ; 
cones  5  and  7,  5""f ;  cone  9,  ]3""f.  Plasticity  is  not  destroyed  until 
cone  06  is  reached,  but  steel  hardness  is  developed  at  cone  02.  Less 
than  lO'^c  absorption  api)ears  at  cone  02,  and  a  vesicular  structure  is 
developed  above  cone  3.     The  fired  structure,  from  cone  02  to  cone  3, 


CLAY  RESOURCES  AXD  CERAMIC  INDUSTRY 


317 


is  soniu],  and  stony,  with   a   smooth   surface  texture, 
total  linear  shriiii\a;^('.  phistic  basis,  is  l.l.S';,  at  eone  '^. 
|)oiiit  is  cone  1:5.     Tlie  ehiy  nii^dit  Wud  some  use  as  a  vit 
hurt',  eream,  or  i)ink  bodies  burned  between  the  limits 
eone  8. 

TABLE    No.  22. 
M.    Buff-Burning    Clays. 
B.   Non -refractory  clay.s,  .softening  point  cone  27- 


Tlie  maximum 

The  soften iiig 

rifyino  ao-ent  in 

of  eone  02  and 


a.   Open- 

l)nrning,   not 

below   6'/f 

apparent 

porosity   lielow 

cone    10. 

;i. 

Medium  to 

high  strength. 

Soften- 

('lav 

ing  pt. 

No! 

Tc  S.W. 

c/c  P.W. 

</(  W.P. 

D.T.S'. 

%  D.V.S. 

%  D.L.S. 

in  cones 

ly 

11. u 

12.2 

23.2 

463 

21.9 

6.8 

23 

25 

19.3 

18.9 

38.2 

3  88 

34.0 

10.3 

16 

36 

11.8 

19.2 

31.0 

566 

19.9 

6.3 

26 

it4 

9.1 

13.3 

22.4 

207 

17.7 

5.6 

17 

95 

7.3 

12.3 

19.6 

241 

14.7 

4.7 

18 

it  9 

12.5 

14.2 

26.7 

538 

23.7 

7.4 

26-27 

114 

8.3 

13.9 

22.2 

231 

15.6 

5.0 

17-18 

i:55 

15.7 

14.3 

30.0 

437 

29.1 

8.8 

1G8 

9.0 

16.7 

25.7 

315 

16.1 

5.1 

1G9 

8.3 

15.1 

23.4 

246 

15.5 

5.0 

19-20 

173 

20.0 

21.3 

41.3 

391 

33.0 

10.0 

255 

20.6 

21.0 

41.6 

238 

35.2 

10.6 

26 

283  A 

9.3 

34.2 

43.5 

3  47 

11.7 

3.7 

26-27 

283  B 

11.2 

15.7 

26.9 

10.   Low 

369 
strength 

19.9 

6.3 

Soften- 

Clay 
No. 

ing  pt. 

%  S.W. 

%  P.W. 

%  W.P. 

D.T.S. 

%  D.V.S. 

%  D.L.S. 

in  cones 

16 

9.3 

17.9 

27.2 

88 

16.7 

5.3 

18 

55 

3.9 

15.7 

19.6 

97 

7.3 

2.4 

18 

82 

6.3 

20.6 

26.9 

129 

10.5 

3.3 

23-26 

88 

2.8 

16.9 

19.7 

175 

4.6 

1.5 

1 1 1 

9.9 

16.3 

26.2 

165 

18.4 

5.8 

19-20 

HIT 

8.8 

21.5 

30.3 

62 

14.5 

4.7 

23 

170 

5.3 

19.5 

24.8 

105 

9.1 

2.9 

238 

4.3 

16.8 

21.1 

38 

7.8 

2.5 

269 

31.5 

36.8 

68.3 

166 

39.8 

11.9 

284 

5.0 

18.7 

23.7 

80 

8.6 

2.8 

Clay 
No. 

166 


Dense-burning,  less  tlian   6%  apparent  porosity  below  cone   10. 
11.   Low  strength. 


%  S.W. 
11.5 


%  P.W. 
24.1 


%  W.P. 
35.6 


D.T.S'. 
117 


<7r  D.V.S. 
18.8 


%  S.W. 
%  P.W. 
%  W.P. 
D.T.S. 
%  D.V.S. 
%  D.L.S. 


%  D.L.S. 
5.9 


Soften- 
ing pt. 
in  cones 
13 


=:  Per  cent  shrinkage  water. 
=  Per  cent  pore   water. 

—  Per  cent  water  of  plasticity.  .^,       ^  j 
=  Dry  transverse  strength,  pounds  per  square  inch,  without  sand. 

—  Drving  shrinkage,   per  cent   dry  voIum«. 

—  Calculated  linear  drying  shrinkage,  per  cent  diy  length. 


318 


DIVISION  OF  MINES  AND  MINING 


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CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


319 


Al)sorption  and  linear  shrinkage  curves  for  clays  of  class  9. 


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DIVISIOX  OF  MINES  AND  MINING 


Absorption  and  linear  shrinkage  curves  for  clays  of  classes  10  and   11. 


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(LAY  RESOURCES  AND  CEUAMIC  INDUSTRY  321 

III.    RED-BURNING   CLAYS. 

A.   Open- Burning,    Do    Not    Attain    Less    Than    6%    Apparent    Porosity    at    Any 

Temperature   Short  of  Actual    Fusion. 

12.    ]\I{'(liuiii  1()   1 1  lull   strength. 

^'o.  8  (p.  163).  Riverside  County.  Alberhill  C.  &  C.  Co.  "Red  Clay 
N'o.  2."  This  is  used  ]ii'iii(M]ially  as  a  rcd-eolorinp-  day  in  the  nianu- 
facturc  (if  I'licc  hi-ieiv  and  other  higli-^'rade  red-bnrnetl  pi'oduets.  It  is 
siiiiilai'  in  its  properties  to  No.  7  (class  13),  but  is  not  (juite  as  uniformly 
line-grained,  has  gi'eater  sliiiidvage  and  strengtli,  and  vitrifies  more 
tlioi-ongldy  at  eone  13.  The  eolors  ai-e  as  follows:  dry,  11"1);  wet,  11"; 
cones  010  to  3,  H'b;  cone  5,  !)"b ;  cone  7,  7"b;  cones  9  and  11,  5";  and 
eone  13,  5"'"b  (flashed).  Finger-nail  liardne.ss  is  found  at  cone  08, 
and  steel  liardness  at  coiic  !>.  The  total  linear  shrinkage,  i)lastic  basis, 
at  eone  13,  is  1.1.8^7  .  Tlie  softening  i)oint  is  cone  l!)-2().  The  best 
firing  range  is  from  cone  08  to  cone  11,  and  especially  good  results  are 
obtained  from  cone  1  to  cone  7. 

No.  18  (p.  1()3).  Riversi(h'  County.  Alberhill  C.  &  C.  Co.  "Clark 
Tuiiiiel  ^Mottled."  This  is  a  i)lastic  red-burning  clay,  used  in  sewer- 
pi  l)e  mixes  to  increase!  the  vitrification  range  of  the  mix.  It  contains 
15.6/^  of  -|-2()()-mesh  .sand,  has  excell^init  'plasticity,  medium  dry 
strength,  and  in  the  dried  state  is  medium  hard  and  has  a  medium 
grain.  The  colors  are:  drj^  ll"b;  wet,  9";  cones  010  to  06,  9'b;  cones 
04  to  02,  n/;  cones  1  to  7,  9'i;  cones  9  to  11,  5".  Finger-iuiil  hardness 
is  (levelo])ed  at  cone  010,  and  steel  hardness  at  cone  3.  The  total  linear 
shrinkage,  plastic  basis,  is  17.8%  at  cone  11.  The  softening  point  is 
eone  19.    The  be.st  firing  range  is  from  cone  1  to  cone  11. 

No.  24  (]).  163,).  Riverside  County.  Albei-hill  C.  &  C.  Co.  "West 
Tunnel  ^Mottled."  This  is  a  red-burning  clay  used  in  sagger  mixes 
and  face  brick.  It  contains  13.8%  of  -|--00-mesh  .sand  and  has  smooth 
and  .strong  plasticit}',  medium  dry  strength.  In  the  dry  condition  it  is 
medium-hard,  fine-grained,  close-textured,  with  a  tendency  to  laminate. 
The  colors  are:  dry,  ll"d;  wet,  9";  cones  010  to  04,  9'b; 'cones  02  to  3, 
7"b  ;  cone  5,  9"  ;  cone  7,  5"k ;  cone  9,  5"i ;  cones  11  and  13,  1'".  Finger- 
nail liardne.ss  develops  below  cone  010,  and  steel  hardness  at  cone  7. 
The  specimens  appear  to  be  well  vitrified  at  cones  11  and  13,  but  the 
absorptions  are  greater  than  10%,  at  these  temperatures.  Some  of  the 
test  pieces  are  slightly  cracked.  The  maximum  total  linear  shrinkage, 
plastic  basis,  is  14.2%  at  cone  11.  The  softening  point  is  cone  18-19. 
The  best  firing  range  is  from  cone  5  to  cone  11.  Slight  bloating  is 
noted  at  cone  13. 

No.  26  (p.  163).  Riverside  County.  Alberhill  C.  &  C.  Co.  "West 
Yellow  Stripping."  This  is  used  for  face  brick  and  sewer-pipe.  It 
contains  21.8%  of  -4-200-mesh  sand  and  has  a  smooth  and  strong  plas- 
ticity, exceptionally  high  diy  strength,  high  drying  shrinkage,  and 
medium  firing-slirinkage.  It  laminates  easily,  warps  badly  in  drying, 
and  in  the  dry  state  is  hard,  with  a  fine  grain  and  close  texture.  The 
colors  are:  dry,  19";  wet,  19"i;  cone  010,  ll"b,  cones  08  and  06,  9"; 
cone  04,  11" ;  cones  02  to  3,  7" ;  cones  5  and  7,  5" ;  cone  9,  7" ;  cone  11, 
5'";  cone  13,  5'"i.     The  fired  colors  are  excellent  for  the  darker  shades 

-'1 — 54979 


822  DIVISION  OF  MINES  AND  MININO 

of  face  brick.  Piiifrer-uail  liardiiess  is  present  in  the  dry  condition, 
and  steel  hardness  appears  at  cone  1.  Absorptions  below  10/^  appear 
at  cone  02.  Bloatinff  lieojins  at  cone  i).  The  total  maximum  linear 
shrinka<re,  plastic  basis,  is  ISSt'/i ,  at  cone  7,  and  bloatinjr  appears  at 
liijrher  temperatures.  Tlie  best  firinpr  ran<re  is  from  cone  02  to  cone  7. 
The  clay  is  especially  valuable  for  its  hi^h  dry  and  fired  strength,  and 
its  wide  vitrification  range  at  commercial  temperatures. 

No.  32  (\).  205) .  San  Diego  County.  Linda  Vista.  Vitrified  Products 
Co.  A  yellow  clay-shale  of  Tertiary  age.  It  is  used  for  structural 
ware.  It  has  good  plasticity,  medium  high  dry  strength,  and  good  dry 
condition.  Some  lime  is  present,  wliicli  does  no  harm  if  tlie  larger  lime 
boulders  are  avoided  in  mining,  and  if  the  mix  is  well  prepared  in  the 
plant.  The  colors  are:  dry,  17"d ;  wet,  17";  cone  010.  ll'b;  cone  08, 
11' ;  cones  06  to  02,  9' ;  cones  1  and  3,  5"'k.  Finger-nail  hardness  is 
present  in  the  dry  state,  and  steel  hardness  appears  at  cone  04.  In  the 
sample  tested,  the  maximum  total  shrinkage,  plastic  basis,  is  11.2%,  at 
cone  1.  The  absorption  at  this  point  is  8.7%.  and  at  higher  tempera- 
tures bloating  begins,  accompanied  by  the  development  of  yellow-green 
colors  typical  of  the  presence  of  lime.  It  is  possible  that  the  sample 
contains  more  lime  than  is  usually  present  in  the  material  delivered 
to  the  plant.    The  best  firing  range  is  from  cone  010  to  cone  1. 

No.  3.-)  (p.  202).  San  Diego  County.  Cardiff.  C41adding,  ]\IcBean 
and  Co.  This  is  a  red-burning  face-brick  clay  with  excellent  plas- 
ticity, high  dry  strength,  and  safe  drying  properties.  It  contains  16.4% 
of  -j-200-mesh  sand.  In  the  dry  state  it  is  hard,  and  has  a  medium 
grain  and  open  texture.  The  colors  are :  drv,  17"f ;  wet,  15"d ;  cones 
010  and  08,  ll"b;  cones  06  and  04,  ll'b;  cone  01,  9'b;  cone  1,  9';  cones 
3  to  7,  7";  cones  9  and  11,  5"i ;  cone  13,  13"i.  The  fired  colors  are 
excellent  intermediate  shades  for  face  brick.  Finger-nail  hardness 
appears  below  cone  010,  and  steel  hardness  at  cone  1.  Vitrification  is 
well  advanced,  but  not  complete,  at  cone  13.  The  total  linear  shrink- 
age, plastic  basis,  at  cone  13,  is  14.6%.  The  softening  point  is  cone 
17-18.  The  best  firing  range  is  from  cone  1  to  above  cone  13.  The 
long  firing  range  and  high  dry  strength  of  this  clay  are  its  specially 
desirable  features. 

Vrt.  i()  (p.  203).  San  Diego  County.  Xear  Carlsbad.  Pacific  Clay 
Products  Co.  "Kelly  Ranch  Yellow."  This  is  a  red-burning,  i)lastic 
clay  with  a  long  vitrification  range,  from  a  bed  underlying  that  from 
which  sample  Xo.  39  was  taken.  It  is  suitable  for  the  manufacture  of 
face  brick,  sewer-pipe,  roofing  tile,  and  similar  products.  The  sample 
contains  4.8%  of  -|-200-mesh  sand.  It  has  a  smooth,  strong  plasticity, 
high  dry  strength,  and  the  dry  .structure  is  hard,  fine-grained,  and 
dense.  The  colors  are:  dry,  17"'b;  wet,  17"i;  cones  010  to  04,  9'b; 
cone  02,  9';  cones  1  to  5.  9'i;  cones  7  and  9.  o".  The  fired  colors  cover 
a  good  range  of  brilliant  reds  for  face  brick  and  roofing  tile.  Finger- 
nail hardness  is  approached  in  the  dry  state,  and  steel  hardness  appears 
at  cone  08.  Porosity  under  10 /r  is  found  at  cone  1.  and  bloating  begins 
above  cone  5.  The  total  maximum  linear  shrinkage,  plastic  basis,  is 
18.9%  at  cone  9.  The  softening  point  is  cone  18-19.  The  best  firing 
range  is  from  cone  02  to  cone  13. 

No.  6')  (p.  141).    Orange  County.    Brea.    Brea  Brick  Co.     This  is  a 


CLAY  RESOURCES  AND  CERA^IIO  INDUSTRY  323 

rctl-buniinji:  surface  cIjiv  suitable  \\)V  the  nianur.U'turc  oi"  coinnuiu  brick. 
It  effervesces  sliprlitly  in  iiydrochloric  acid.  The  jilasticity  is  good, 
with  a  tendency  id  become  sticky  Avilli  exc(\ss  watiu'.  tlie  diy  strength  is 
liU'diuin  hitrli.  and  the  dry  condition  is  hard,  (h'use,  and  granular.  Tt 
contains  4').'2'/r  of  -|--'**'-J"t'^h  sand.  The  colors  are:  drv,  17'"b;  Avet, 
l.V'k;  cones  010  and  08,  il'b;  cone  06,  !»';  cone  04,  g'iTcone  02,  9'k; 
cones  .'{  and  5,  5'k;  cone  7,  5"in.  The  fired  colors  are  excellent  for 
common  brick.  Finger-nail  hardness  is  ol)tained  below  cone  010,  and 
steel  hardness  develops  at  cone  3.  Vitrification  is  comi)lete  at  cone  7, 
and  bloating  begins  below  cone  !).  The  fired  condition  is  souiul,  open, 
and  strong.  The  nuiximum  total  linear  shi-inkage,  plastic  basis,  is 
11.9 /( ,  at  cone  7.  The  best  firing  range  is  from  cone  010  to  coti(>  7, 
and  good  structures  are  obtained  from  cone  3  to  cone  7. 

No.  6.9  (]).  169).  liiverside  County.  10  m.  south  of  Coi-ona.  Emsco 
Clay  Co.  "Red  Horse."  This  is  a  red-burning  clay  with  smooth, 
strong  plasticity.  It  is  suitable  as  an  ingredient  of  red  earthenware, 
roofing  tile,  face  brick,  and  sewer-pipe  mixes.  The  sample  contains 
I'-i.H'/r  of  -|-200-mesli  sand.  The  dry  strength  is  medium,  and  the  dry 
condition  is  medium  hard,  fine-grained  and  close-textured.  The  colors 
are:  dry,  9'b;  wet,  9'i ;  cones  010  to  04,  7'b ;  cones  02  to  3,  9';  cone  5, 
7'';  cone  7  to  11,  5''i.  The  fired  colors  cover  an  interesting  range  of 
deep  reds.  Finger-nail  hardness  is  developed  below  cone  010,  and  steel 
hardness  at  cone  04.  Vitrification  is  practically  complete  at  cone  7, 
but  the  apparent  porosity  is  still  above  8  per  cent.  All  test  pieces 
above  cone  08  are  slightly  cracked.  The  fired  condition  is  strong, 
tough  and  fine-grained.  The  total  linear  shrinkage,  plastic  basis,  at 
cone  7,  is  14.4%.  The  softening  i)oint  is  cone  18-19.  The  best  firing- 
range  is  from  cone  04  to  cone  7.  [The  shrinkage  and  apparent  porosity 
data  at  cones  11  and  13  were  lost.  See  absorption  curve  for  general 
trend.] 

Xo.  73  (]).  169).  Riverside  County.  Em.sco  Clay  Co.  "Bone." 
Although  this  is  locally"  classed  as  a  bone  clay  on  account  of  its  pisolitic 
structure  in  the  raw  state,  it  is  lateritic,  and  contains  so  much  iron  as 
to  give  a  low^  fusion  point.  It  contains  46.8%  of  +200-mesh  material. 
The  iilasticity  is  spongy,  ])ut  fairly  strong,  the  dry  strength  is  medium, 
and  the  dry  condition  is  granular,  and  o])en-textured.  The  colors  are : 
dry,  9'd;  wet,  ll'i ;  cones  010  to  04,  ll'f ;  cones  02  to  5,  7'^b ;  cone  7  to 
11,  9"'b ;  cone  13,  5''''k.  The  fired  colors  are  suitable  for  red  face  brick 
and  roofing  tile.  Finger-nail  hardness  is  develoi)ed  below  cone  010,  and 
steel  hardness  at  cone  1.  All  fired  test  pieces  are  sound,  granular,  and 
strong.  Vitrification  is  complete  at  (approx.)  cone  7,  bej^ond  which 
temperature,  bloating  gradually  develops.  The  maximum  total  linear 
shrinkage,  plastic  basis,  is  9.2^t,  at  cone  7.  Absori)tions  below  10% 
are  obtained  at  cone  02  or  higher.  The  softening  point  is  cone  15. 
The  best  firing  range  is  from  cone  02  to  cone  7.  The  clay  can  be  used 
as  a  coloring  agent,  and  to  prolong  the  vitrification  range  of  red-burned 
structural  ware. 

Xo.  100  (p.  171).  Riverside  County.  Alberhill.  G.,  McB.  &  Co. 
"Yellow  Striii])ing."  This  is  an  impure,  sandy  clay  that  is  used  in 
face-brick  and  sewer-pipe  mixtures.  It  effervesces  slightly  in  hydro- 
chloric acid.     The  plasticity  is  good,  the  dry  strength  is  exceptionally 


324  DIVISION  OF  MINES  AND  MINING 

high,  and  in  the  dried  condition  the  clay  has  finger-nail  hardness,  and 
is  dense  and  fine-grained.  It  contains  20.8%  of  4-200-inesh  sand. 
The  colors  are:  dry,  15"d ;  wet,  17'';  cones  010  to  02,  9'b;  cone  1,  9'i; 
cones  3  to  11,  5'i.  Steel  hardness  is  developed  at  cone  06.  Absorptions 
below  10%  are  obtained  from  cone  02  to  cone  9,  inclusive.  All  fired 
test  pieces  are  sound,  and  have  a  stony  structure.  Vitrification  is 
complete  at  cone  5,  and  bloating  begins  above  cone  9.  The  maximum 
total  linear  shrinkage,  plastic  basis,  is  17.3%,  at  cone  5.  The  softening 
])oint  is  cone  14-15. 

No.  ion  (p.  171).  Riverside  County.  Alberhill.  G.,  IMcB.  &  Co. 
"Sloan  lied."  This  is  a  red-burning  clay  with  good  i)lasticity,  medium 
dry  strength,  and  in  the  dried  condition  it  is  soft,  medium-grained,  and 
open-textured.  It  contains  17.0%  of  -|-200-mesh  sand.  It  is  used  for 
face  brick,  roofing  tile,  and  .similar  products.  The  colors  are :  dry, 
ll'd;  wet,  9'k;  cones  010  to  5,  9'b;  cone  7,  7"b;  cones  9  to  13,  5"i. 
Finger-nail  hardness  is  developed  at  cone  06,  and  steel  hardness  at 
cone  1.  The  fired  structures  are  all  sound  and  stony,  with  a  slightly 
roughened  surface  texture.  Absorptions  below  10%  are  obtained  at 
cone  7  or  above.  The  total  linear  shrinkage,  plastic  basis,  at  cone  13, 
is  15.0%.    The  softening  point  is  cone  18-19. 

No.  112  (p.  178).  Riverside  County.  Alberhill.  P.  C.  P.  Co. 
' '  Hoist  Pit  Blue. ' '  This  is  a  plastic,  pink-burning  clay  that  is  used  in 
sewer-pipe  mixes.  The  plasticity  is  excellent,  the  dry  strength  is 
medium,  and  in  the  dried  condition  the  clay  is  soft,  medium-grained, 
and  open-textured.  It  contains  25.0%  of  -|-200-mesh  sand.  The  colors 
are :  dry,  17'"b ;  wet,  19''k ;  cones  010  to  02,  7'd ;  cones  1  to  7,  7''d ; 
cone  9,  9'''d ;  cones  11  and  13,  13'"i.  Finger-nail  hardness  appears 
below  cone  010,  and  steel  hardness  at  cone  1.  Absorptions  below  10% 
are  obtained  at  cone  7.  The  fired  structure  is  sound  and  heterogeneous, 
and  the  fired  surface  texture  is  smooth.  The  total  linear  shrinkage, 
plastic  basis,  at  cone  13,  is  16.1%.    The  softening  point  is  cone  19. 

No.  113  (p.  176).  Riverside  County.  Alberhill.  P.  C.  P.  Co. 
"Hoist  Pit  Red."  This  is  a  red-burning  sandy  clay  of  use  in  sewer- 
pipe  mixes,  roofing  tile,  red  earthenware,  etc.  It  contains  18.6%  of 
-|-200-mesh  sand.  The  plasticity  is  excellent,  the  dry  strength  is 
medium  high,  and  in  the  dried  condition  the  clay  is  hard,  brittle,  fine- 
grained and  close-textured.  The  colors  are :  dry,  9'b ;  wet,  7'i ;  cones 
010  to  7,  9';  cones  9  to  13,  9"'.  Finger-nail  hardness  (nearly)  is 
present  in  the  dried  state,  and  steel  hardness  appears  at  cone  3.  The 
fired  condition  is  sound  and  fine-grained,  and  the  fired  surface  texture 
is  slightly  rough.  The  total  linear  shrinkage,  plastic  basis,  at  cone  13, 
is  11.3%.     The  softening  point  is  cone  23-26. 

No.  117  (p.  131).  Santa  Cruz  County.  Castroville.  Joe  Area. 
This  is  an  excessively  plastic  surface  clay,  that  can  almost  be  classed 
as  an  adobe.  It  is  used  for  making  hand-made  roofing  tile  on  a  small 
scale.  It  has  an  exceptionally  high  dry  strength,  but  must  be  dried 
carefully  to  prevent  warping  and  ei-acking.  In  the  dried  condition  it 
is  dense,  fine  grained,  and  has  finger-nail  hardness.  The  colors  are : 
dry,  17"'b ;  wet,  17"'i ;  cones  010  to  06,  9'b ;  cone  04,  9' ;  cone  02,  9"i. 
Steel  hardness  develops  at  cone  02.  Bloating  is  well  advanced  at  cone  1. 
All  test  pieces  cracked  on  firing.    The  maximum  total  linear  shrinkage, 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  325 

plastic  basis,  is  18.0%,  at  cone  02.  Most  of  the  shrinkage  takes  place 
iluring  drying.  The  best  firing  range  is  from  cone  010  to  cone  02. 
The  short  vitrification  range  and  the  poor  drying  qualities  of  this  clay 
preclude  its  general  use  for  structural-clay  products. 

No.  119  (y).  1^).  Contra  Costa  County.  Point  Richmond.  Richmond 
Pressed  Brick  Co.  This  is  one  of  tlie  tyi)ical  red-burning  Tertiary  clays 
of  the  San  Francisco  Bay  region  that  are  widely  used  for  the  manufac- 
ture of  common  brick  and  buikling  tile.  As  ground,  the  sample  con- 
tains 43.2%  of  +200-mesh  sand.  The  phisticity  is  good,  the  dry 
strength  is  medium,  and  the  dried  condition  is  hard,  medium-grained, 
and  open-textured.  The  colors  are :  dry,  17'^^' ;  wet,  17""i ;  cone  010, 
13"b;  cone  08,  ll^'b;  cones  06  and  04,  9'';  cone  01,  7"i;  cone  1,  5'k. 
Steel  hardness  is  developed  at  cone  04-f-.  Vitrification  is  complete  at 
cone  1,  and  bloating  begins  at  sliglitly  higher  temperatures.  The  fired 
.structure  is  sound  and  fine-granular,  and  slightly  roughened  surface 
textures  are  obtained.  The  maximum  total  linear  shrinkage,  plastic 
basis,  is  12.1%,  at  cone  1. 

No.  155  (p.  151).  Placer  County.  Lincoln.  Gladding,  McBean  &  Co. 
"Pit  Sand."  This  is  a  red-burning  sand-clay  mixture  that  is  used  in 
tlie  manufacture  of  roofing  tile,  sewer  pipe,  and  other  red-body  ware. 
The  residue  on  200-mesh  is  31.8%.  The  ])lasticity  is  fair,  the  dry 
strength  is  medium  high,  and  in  the  dried  condition  it  is  hard,  medium- 
grained,  and  open-textured.  The  colors  are:  dry,  17''"d ;  wet,  17""; 
cones  010  to  06,  13";  cones  04  and  02,  1";  cones'l  to  5,  ll"i;  cone  7, 
5"m.  Finger-nail  hardness  is  present  in  the  dried  condition,  and  steel 
liardness  is  developed  at  cone  1.  The  fired  structure  is  sound,  except  for 
light  hair-cracks  on  the  surface.  The  fired  surface  texture  is  rougli. 
Bloating  begins  at  cone  7,  before  the  body  is  vitrified  to  a  low  absorj)- 
tion.  The  maximum  total  linear  shrinkage,  plastic  basis,  is  15.0% ,  at 
cone  5. 

iVo.  77^  (p.  66).  Butte  County.  Oroville.  Quincy  i-oad.  This  sample 
is  representative  of  a  residual  deposit  of  decomposed  granite.  The  plas- 
ticity is  fair,  the  dry  strength  is  medium  high,  and  in  the  dried  condition 
it  is  medium  hard,  coarse-grained,  and  open-textured.  The  colors  are : 
dry,  15"d;  wet,  15";  cone  010,  15";  cone  08,  13";  cones  06  and  04,  11'; 
cone  02,  9' ;  cone  1,  7'i.  These  are  good  colors  for  common  brick. 
Steel  hardness  is  not  developed  up  to  cone  1.  the  upper  temperature 
limit  studied.  The  fired  structure  is  .sound  and  granular,  and  the  sur- 
face texture  is  moderately  rough.  The  total  linear  shrinkage,  plastic 
basis,  is  8.2%,  at  cone  1.  The  material  is  suited  for  the  manufacture  of 
common  brick. 

.Vo.  i78  (p.  66).  Butte  County.  Palermo.  Lund  Brick  Yard.  This 
is  a  clay-gravel  mixture  from  a  Tertiary  river  channel  and  is  being  used 
for  the  manufacture  of  common  brick.  Three  separate  samples  were 
taken.  No.  178-1,  2,  and  3,  each  representing  different  phases  of  the 
material.  Only  one  of  these.  No.  178-2,  was  tested  completely.  The 
others  were  fired  to  but  three  different  temperatures  each.  The  differ- 
ences between  the  three  varieties  are  the  result  of  differing  proportions 
of  sand,  silt,  and  gravel.  No.  178-1  contains  51.6%  of  +200-mesh  sand, 
No.  178-2  contains  23.6%,  and  No.  178-3  contains  15.2%.  This  descrip- 
tion covers  No.  178-2,  and  the  reader  is  referred  to  the  tabulated  data 


326  DIVISION  OF  MINES  AND  MINING 

for  the  results  on  the  other  samples.  The  plasticity  is  strong,  but  with  a 
tendency  to  stickiness  when  excess  water  is  used.  Tlie  dry  strength  is 
higli,  and  in  the  dried  condition  it  has  finyer-nail  hardness,  is  medium- 
o-rained,  and  open-textured.  The  tendency  to  laminate  is  pronounced. 
The  colors  are :  dry,  ll'b ;  wet,  ll'i ;  cones  010  to  3,  9'i ;  cone  6,  5'k. 
Steel  hardness  is  developed  at  cone  02,  and  less  than  10/r  absorption  at 
cone  6.  The  fired  structure  is  strong  and  stony,*  with  a  slight  tendency 
to  crack.  The  surface  texture  is  moderately  rough.  The  total  linear 
sliriid<age,  i)lastic  basis,  is  15.8%,  at  cone  6.  The  best  firing  range  is 
from  cone  02  to  cone  6,  for  hard-burned  ware,  and  from  cones  06  to  02 
for  soft-burned  ware.  The  material  makes  a  strong  brick  with  good 
colors,  but  the  irregularity  of  the  de))osit  is  i\u  uncertain  factor  that 
makes  the  close  control  of  shrinkage  difficult. 

No.  180  (p.  77).  Del  Norte  County.  Crescent  City.  Elk  Valley. 
Tliis  is  a  common-brick  clay.  The  ])lasticity  is  good,  the  dry  strengtli 
is  medium,  and  in  the  dried  condition  it  is  hard,  fine-grained,  and  close- 
textured.  It  contains  19.2^/c  of  +200-mesh  sand.  The  colors  are:  dry, 
17''b ;  wet,  IT'^i ;  cones  010  to  06,  9' ;  cones  04  to  3,  9'i ;  cone  6,  5'k. 
Steel  hardness  is  developed  at  cone  1,  and  less  than  10*^/  absorjition  at 
cone  3.  All  test  pieces  are  sound.  The  total  linear  shrinkage,  plastic 
basis,  is  17.5%.  The  best  firing  range  is  from  cone  010  to  cone  3.  The 
clay  is  entirely  suitable  for  the  manufacture  of  red  brick  either  by  the 
soft-mud  or  stiff-mud  process. 

No.  183  (p.  81).  Humboldt  County.  Eureka.  Thompson  Brick  Co. 
This  is  a  common-brick  clay  with  good  i^lasticity,  high  dry  strength, 
and  in  the  dried  condition  it  has  finger-nail  hardness,  is  fine-grained  and 
close-textured.  It  contains  16.8%  of  -|-200-mesh  sand.  The  colors  are: 
dry,  17"d;  wet,  17"k;  cones  010  to  06,  11';  cone  04,  9';  cone  02,  7'i ; 
cone  1,  7'm;  cones  3  and  5,  7"m.  Steel  hardness  is  developed  at  cone 
010,  and  less  than  10%  absorptioji  at  cone  02.  The  fired  structure  is 
generally  sound,  but  with  a  tendency  to  crack.  Bloating  begins  above 
cone  3.  The  maximum  total  linear  shrinkage,  plastic  basis,  is  16.6%.,  at 
cone  3.  The  clay  is  mixed  at  the  ]ilant  with  a  sandier  variety  to  insure 
safer  drying  and  firing. 

No.  183  {]}.  SI).  Humboldt  County.  Eureka.  Second  Slough.  This 
is  a  common  clay  that  has  not  been  used.  It  has  sticky  plasticity,  high 
dry  strength,  and  in  the  dried  condition  it  is  hard,  medium-grained,  and 
close-texturod.  The  colors  are:  dry,  17"d;  wet,  17"k ;  cones  010  to  08, 
9'd ;  cones  06  and  04,  9'b ;  cone  02,  7" ;  cone  1,  5"k ;  cones  3  and  5,  5"m. 
Steel  hardness  and  less  than  10%  absorption  are  developed  at  cone  02. 
The  fired  structure  is  sound,  uji  to  cone  1,  beyond  which  bloating  begins. 
The  maximum  total  linear  shrinkage,  i)lastic  basis,  is  18.9'X,  at  cone  1. 
The  clay  Avould  be  satisfactory  for  common-brick  manufacture,  if 
mixed  with  less  plastic  material. 

No.  199  (p.  74).  Contra  Costa  County.  Port  Costa.  Port  Costa 
Brick  Co.  This  is  a  plastic,  red-burning  Tertiary  shale  that  is  used  for 
the  manufacture  of  common  brick  and  hollow  tile.  There  is  strong 
effervescence  in  hydrochloric  acid.  The  i)lasticity  is  good,  with  a 
tendency  to  stickiness,  and  dry  strength  is  medium,  and  in  the  dried 
condition  it  is  medium-hard,  medium-grained,  and  close-textured.  The 
sample,  as  ground,  contains  40.2%  of  -j-200-mesh  sand.     The  colors  are: 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  327 

dry,  21""f;  wet,  21"";  cones  010  to  04,  ll'b;  com'  02,  })' ;  cone  1,  7"; 
cone  8,  7"k.  Steel  hartlness  is  developed  at  cone  04.  and  less  than  10% 
absorption  at  cone  02.  The  fired  structure  is  sound,  up  to  cone  1,  above 
which  bloatin<r  begins.  The  .surface  texture  is  .sliprhtly  rough.  The  total 
linear  shrinkage.  i)lastic  basis,  is  14.8V,,  at  eoiu^  1.  The  best  firing 
range  is  from  cone  04  to  cone  1. 

.Yo.  505  (p.  282).  Tulare  County.  Porterville.  Black  slate.  This  is 
a  black  slate  that  develops  good  plasticity,  medium  dry  strength,  and 
fires  to  a  red  color.  In  the  dried  condition  it  has  finger-nail  hardness, 
is  coai-se-grained,  and  open-textured.  ft  should  be  finely  ground  to 
avoid  excessive  lamination.  The  colors  are:  dry,  15"'";  wet,  nearly 
black ;  cones  010  and  08,  17"b ;  cone  06,  18"b ;  cone  04,  11" ;  cone  02,  7". 
Steel  hardness  is  developed  at  cone  04.  The  fired  structure  is  sound  and 
strong  and  the  surface  texture  is  I'ough.  The  total  lineai-  shrinkage, 
plastic  basis,  is  1.9'/t .  at  cone  8.  This  should  be  a  good  clay  for  com- 
mon brick  and  hollow  tile. 

No.  211  (p.  131).  Monterey  County.  Near  Monterey  on  Salinas  road. 
Monterey  Mission  Tile  Co.  This  is  an  adobe  clay  that  is  used  for  the 
manufacture  of  hand-made  roofing  and  step  tile.  The  plasticity  is 
strong  and  sticky,  the  dry  strength  is  high,  and  in  the  dried  condition 
it  has  finger-nail  hardness,  is  fine-grained,  and  close-textured.  Serious 
warping  and  cracking  results  in  drving  when  the  clay  is  used  alone. 
The  colors  are:  dry,  15""';  wet,  15""'k ;  cones  010  to  06,  15"  b;  cone 
04.  11".  Steel  hardness  and  less  than  10%  absorption  are  present  at 
cone  010.  All  test  pieces  cracked  in  firing,  and  serious  bloating  takes 
place  at  cone  04.  The  maximum  total  linear  shrinkage,  plastic  basis, 
is  15.4%,  at  cone  06.  This  clay  can  not  be  used  alone,  but  when  grogged 
with  crushed  tile  made  from  the  same  clay,  very  attractive  hand-made 
tile  can  be  made. 

No.  216  and  217  (]).  218).  San  Luis  Obispo  County.  State  highway 
2  m.  south  of  Santa  Margarita.  These  two  samples  are  representative 
of  a  large  deposit  of  red-burning  shale.  The  shale  develops  good 
plasticity  without  the  necessity  of  tine  grinding.  The  dry  strength  is 
medium,  and  in  the  dried  condition  it  is  hard  and  close-textured.  The 
colors  are:  dry,  17"i  to  15";  wet,  15"k;  cones  010  and  08,  11';  cones  06 
and  04,  9'i ;  cone  02,  7'k;  and  cone  1,  7'm.  Steel  hardness  and  less  than 
10^,'  absorption  are  developed  at  cone  02.  The  fired  structure  is  strong, 
but  the  test  pieces  that  were  fired  at  or  above  cone  02  are  slightly 
checked.  The  total  linear  shrinkage,  plastic  basis,  at  cone  1,  is  12.4% 
for  No.  216,  and  13.3%o  for  No.  217.  The  best  firing  range  is  from 
cone  04  to  cone  1.  The  material  seems  entirely  suitable  for  the  manu- 
facture of  hard  or  soft-fired  heavy  clay  products,  and  is  a  possible 
material  for  paving  brick. 

No.  251  {p.  52).  Amador  County.  lone.  Core  drill  hole  No.  57-1, 
Arroyo  Seco  Grant.  This  is  a  red-burning  clay  with  smooth  and 
strong  plasticity,  and  medium  dry  strength.  In  the  dried  condition  it 
is  medium  hard,  fine-grained,  and  close-textured.  It  effervesces  slightly 
in  hydrochloric  acid.  Some  fine  sand  is  present.  The  colors  are:  dry, 
15'd';  Avet,  15'b;  cones  1  and  5,  9"b;  cones  9  and  13,  ll"i.  Steel  hard- 
ness and  less  than  10%  absorption  are  developed  below  cone  1.  Blister- 
ing is  noted  at  cone  13,  otherwise  the  fired  structure  is  sound  and 


328  DIVISION  OF  MINES  AND  MINING 

stony.  TJie  surface  texture  is  smooth.  Tlic  maximum  total  linear 
shrinkage,  plastic  basis,  is  18.8%,  at  cone  9.  The  softening  point  is 
cone  23.    This  clay  is  suitable  for  face  brick. 

No.  261  {p.  159).  Placer  County.  East  of  Lincoln.  Valley  View 
Mine.  This  is  an  iron-stained  kaolin,  witli  fair  plasticity  and  medium 
dry  strength.  In  the  dried  condition  it  is  hard,  fine-grained,  open- 
textured  and  heterogeneous.  The  colors  are:  dry,  ll"d;  wet,  15"b; 
cones  010  to  1,  T'h;  cone  3,  T'd;  cones  5  and  7,  13";  cones  9  and  13, 
15".  Steel  hardness  is  not  developed  at  cone  3.  The  fired  structure  is 
sound,  except  for  a  few  superficial  hair  cracks.  The  surface  texture 
is  moderately  rough.  The  total  lijiear  slirinkage,  plastic  basis,  is  17.7% 
at  cone  13.  The  softening  point  is  cone  28,  yet  it  is  distinctly  a  red- 
burning  clay.  The  material  might  be  used  in  face  brick  and  terra 
cotta. 

13.     Low  Strength. 


o  ■ 


No.  7  (p.  163).  Riverside  County.  Alberhill  C.  &  C.  Co.  "Pink 
Mottled."  This  is  one  of  the  important  face-brick,  roof-tile,  and  floor- 
tile  clays  from  the  Alberhill  district.  It  is  a  fine-grained,  pink-yellow 
mottled  clay  of  medium  hardness,  develops  a  .smooth  and  strong 
plasticity,  and  has  medium  low  dry  strength.  It  contains  14.2%  of 
+200-mesh  sand.  The  colors  are  as  follows:  dry,  ll"d;  wet,  11"; 
cones  010  to  3,  9'b;  cone  5,  7'd;  cone  7.  7'b;  cones  9  and  11,  7";  cone 
13,  7"i.  These  are  good  pinks  and  light  reds  for  face  brick,  floor  tile, 
etc.  At  cone  13,  fine  black  specks  appear,  giving  a  not  unpleasing 
mottled  effect,  which  could  be  reproduced  at  lower  temperatures  by 
flashing.  The  fired  surfaces  have  a  smooth  texture,  capable  of  taking 
a  polish.  Finger-nail  hardness  is  not  developed  until  cone  06  is 
reached.  The  hardness  at  cone  13  is  slightly  less  than  steel,  although 
vitrification  is  not  complete  at  that  temperature.  The  total  linear 
shrinkage,  plastic  basis,  is  10.5%  at  cone  13.  The  softening  point  is 
cone  17.    The  best  firing  range  is  from  cone  06  to  cone  11. 

No.  73  (y).  169) .  Riverside  County.  Emsco  Clav  Co.  "Red."  This 
is  similar  to  No.  8  (class  12)  "Red  Clay  No.  2"  from  the  Alberhill  Coal 
and  Clay  Co.  pits,  but  has  lower  drying  and  firing  shrinkage,  and 
lower  strength.  It  is  used  mainly  as  a  coloring  clay  in  face  brick,  and 
other  high-grade  red-burning  products.  The  residue  on  200-mesh  is 
12.6%.  It  has  a  smooth  and  moderately  .strong  plasticity,  medium  low 
dry  strength,  and  a  soft,  fine-grained,  close-textured  dry  condition. 
The  colors  are:  dry,  7';  Avet,  7'i;  cones  010  to  13,  9',  with  a  slight 
darkening  toward  the  higher  cone  numbers.  Finger-nail  hardness  is 
developed  below  cone  010  and  steel  hardness  at  cone  3.  The  fired 
structure  is  tough  and  stony.  Tlie  total  linear  firing  shrinkage,  plastic 
basis,  is  12.5%,  at  cone  13.  The  softening  point  is  cone  20.  The  best 
firing  range  is  from  cone  02  to  cone  13.  Vitrification  is  practically 
complete  at  cone  11. 

No.  122  (p.  53).  Amador  County.  lone.  Arroyo  Seco  Grant,  Jones 
Butte.  Leased  by  Stockton  Fire  Brick  Co.  Laterite.  This  is  a  true 
laterite  for  which  no  ceramic  uses  have  yet  been  found,  but  which 
occurs  in  sufficient  abundance  to  be  of  possible  interest.  The  sample 
contains  a  large  proportion  of  non-plastic  grains,  and  the  plasticity 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  329 

is  weak  and  sliort.  Tlie  dry  .sti-o]i<>:lli  is  nuHliiuu  low,  and  the  dried 
condition  is  modiuiii  liard,  incdium  frrained,  and  open-textured.  The 
colors  are:  dry,  5";  wet,  'Vi;  cones  OK)  to  :{,  5";  cones  5  and  7,  9"'; 
cone  9,  9"i ;  eone  11,  ll"k.  Steel  liardness  appears  at  cone  1.  Less 
than  10%  absori)tion  is  i)resent  at  cone  f}.  The  fired  structure  is 
^n-anular  and  hair-craeked.  The  total  linear  slirinkajje,  plastic  basis, 
at  cone  11,  is  17.5%.    The  softening  point  is  cone  17-18. 

No.  i:ri  (]).  62).  Amador  roniily.  lone.  "Newman  Red  Mottled." 
This  is  a  red-bnrniiifif  clay  witli  «?ood  ]>]asticity,  low  dry  strength,  and 
in  the  dried  condition  it  is  very  soft,  fine-gi-ained,  and  close-textured. 
It  contains  'A:2%  of  -f'200-mesh  sand.  The  colors  are:  dry,  9"b;  wet, 
!)";  cones  010  to  02.  9'));  cones  1  to  7,  9';  cones  9  to  13,  7'.  Steel 
hardness  appears  at  cone  1,  and  less  than  10%j  absorption  at  cone  11. 
The  fired  structure  is  stony,  and  at  cones  11  and  13  several  tension 
cracks  appeared  during  firing.  The  total  linear  shrinkage,  plastic 
basis,  at  eone  13,  is  20.0%.  The  softening  i)oint  is  eone  23-26.  The 
best  firing  range  is  from  eone  1  to  cone  9.  The  clay  can  be  used  as  a 
coloring  clay  for  face  brick,  roofing  tile,  and  similar  ware. 

Xo.  171  (p.  136).  Xeva(hi  Connty.  Xortli  F.loomfield  road.  This  is  a 
i-ed-burning  clay  tliat  could  be  used  for  common-brick  manufacture. 
The  plasticity  is  fair,  the  dry  strength  is  medium  low,  and  in  the  dried 
condition  it  is  hard,  fine-grained,  and  close  textured.  A  tendency  to 
develop  drvinu-  cracks  was  noted.  Tlie  colors  are:  dry,  17'f;  wet, 
21"';  cones  010  to  06,  ir)"b;  cone  04,  15"d;  cone  02,  11';  cone  1,  9'. 
The  fired  colors  are  suitable  for  common  brick,  roofing  tile,  etc.  Steel 
hardness  appears  at  eone  02,  and  less  than  10%  absorption  at  cone  1. 
The  fired  structui'e  is  stony,  and  is  sound  except  for  a  few  small  cracks, 
which  may  have  been  formed  during  drying.  The  surface  texture  is 
snu)oth.  The  total  linear  shrinkage,  plastic  basis,  is  16.1%,  at  eone  1. 
Xon-plastics  should  be  added. 

No.  1.98  (p.  125).  Marin  County.  San  Rafael.  '  McNear  Brick  Co. 
Til  is  is  a  red-burning,  sandy,  clay-sliale  that  develops  sufficient  plas- 
ticity for  brick  and  liollow-tile  making.  The  dry  strengtli  is  medium- 
low,  and  in  tiie  dried  condition  it  is  medium-hard,  coarse-grained,  and 
open-textured.  Tlie  sample  as  ground  contains  55.8%  of  +2^^^-"i^^'' 
material.  The  colors  are:  dry,  15"b ;  wet,  15"i ;  cones  010  and  08,  7'b ; 
cones  06  and  04,  9'b;  cones  02  to  6,  9"b.  Steel  hardness  is  developed 
at  cone  1.  The  fired  structure  is  coarse-granular  and  open,  and  hair- 
cracks  are  prominent,  especially  when  fired  above  coiu'  1.  The  total 
linear  shi'inkage,  plastic  basis,  is  11.8%),  at  cone  6.  The  best  firing 
range  is  from  cone  04  to  cone  6.  The  sample  contains  more  non- 
plastic  nuitter  than  the  normal  run-of-pit  material. 

No.  218  {p.  IHl).  Riverside  County.  8  m.  south  of  Corona.  This  is 
a  pink-mottled  clay  with  excellent  plasticity  and  medium-low  dry 
strength.  It  is  similar  to  No.  72  (Emsco  Red).  In  the  dried  condition 
it  is  medium-hard,  brittle,  fine-grained  and  close-textured.  The  colors 
are :  dry,  ll'b ;  wet,  9'i ;  cones  010  to  3,  11' ;  cone  5,  7'b.  Steel  hardness 
is  developed  at  cone  3.  The  fired  structure  is  sound  and  stony  and  the 
surface  texture  is  smooth.  The  total  linear  shrinkage,  plastic  basis,  is 
19.5%,  at  cone  11.  The  softening  point  is  cone  23.  The  clay  is  suitable 
for  the  manufaeture  of  face  brick,  roofing  tile,  and  similar  products. 


330 


DIVISION  OF  MINES  AND  MINING 


No.  256  (p.  52).  Amador  County.  Tone.  Core  drill  hole  No.  60, 
Arroyo  Seco  Grant.  This  is  a  red-burning  clay  with  good,  but  sticky, 
plasticity  and  medium-low  dry  strength.  In  the  dried  condition  it  is 
medium-hard,  fine-grained,  and  open-textured.  The  colors  are:  dry, 
n"d  ;  Avet,  11" ;  cone  1,  9" ;  cone  5,  7"i ;  cone  9,  9"' ;  cone  13,  9'"i.  Steel 
hardness  is  develo])ed  at  cone  5,  and  less  tlian  '[{Y/<  absor])tion  at  cone 
13.  Tlie  fired  structure  is  weak  and  hair-cracked.  The  total  linear 
shrinkage,  plastic  basis,  at  cone  13,  is  20.3 /< .  The  softening  point  is 
cone  19-20.  This  is  not  a  good  clay,  but  could  be  used  as  part  of  a 
face-brick  mixture. 


TABLE   No.  24. 

III.   Red-Burning   Clays. 

A.  Opeii-buniins,  tlo  not  attain   less  than   6%   apoarent  porosity  at  any  temperature 

short  of  actual  fusion. 

12.   Medium  to  high  strength. 


flay 

Soften- 
ing pt. 

No.          % 

S.W. 

%  P.W. 

%  W.P. 

D.T.S. 

%  D.V.S. 

</o  D.L.S. 

in  cones 

8 

11.7 

17.6 

29.3 

221 

21.1 

6.3 

19-20 

IS 

20.7 

21.6 

42.3 

305 

34.7 

10.4 

19 

24 

13.2 

19.7 

32.9 

252 

23.1 

7.0 

26 

28.7 

11.6 

40.3 

1569 

56. S 

16.1 

32 

16.0 

20.1 

36.1 

794 

27.6 

8.4 

35 

19.1 

12.8 

31.9 

1094 

37.3 

11.1 

17-18 

40 

22.7 

12.8 

35.5 

1412 

44.3 

13.0 

18-19 

65 

11.2 

12.9 

24.2 

569 

22.1 

6.9 

6U 

12.1 

15.4 

27.5 

265 

23.4 

7.3 

18-19 

73 

8.5 

13.5 

22.0 

334 

16.8 

5.2 

15 

100 

36.6 

12.8 

49.4 

1821 

71.4 

11.9 

14-15 

105 

11.4 

17.4 

28.8 

235 

21.0 

6.4 

18-19 

112 

11.9 

19.7 

31.6 

291 

20.8 

6.5 

19 

113 

13.4 

13.5 

26.9 

509 

26.2 

8.0 

23-25 

117 

30.4 

10.5 

40.9 

H-990 

63.0 

17.8 

119 

9.5 

13.5 

23.0 

374 

18.5 

5.8 

155 

23.3 

16.6 

39.9 

580 

42.3 

12.2 

176 

9.9 

19.2 

29.1 

615 

16.7 

5.3 

178-1 

22.6 

14.1 

36.7 

905 

44.1 

12.9 

17  8-2 

18.0 

12.8 

30.8 

1224 

35.8 

10.7 

17  8-3 

10.3 

14.7 

25.0 

498 

19.5 

6.1 

180 

18.6 

18.8 

37.4 

300 

32.5 

9.9 

182 

22.1 

10.0 

32.1 

1181 

44.7 

13.2 

183 

24.3 

14.4 

38.7 

-H983 

46.4 

13.5 

1!»9 

12.0 

14.3 

26.3 

352 

23.3 

7.3 

206 

5.1 

15.3 

20.4 

340 

9.6 

3.1 

214 

28.5 

12.1 

40.6 

-HlOOO 

54.4 

15.5 

216 

8.0 

15.8 

23.8 

305 

15.3 

4.9 

217 

10.5 

15.5 

25.9 

306 

19.9 

6.3 

•221 

21.2 

14.7 

35.9 

453 

39.0 

11.6 

26 

251 

17.6 

17.9 

35.5 

381 

31.4 

9.5 

23 

261 

17.1 

25.6 

42.7 
13.   Low 

289 
strength. 

26.8 

8.2 

28 
Soften- 

CMay 

ing  pt. 

No.          % 

S.W. 

%  P.W. 

%  W.P. 

D.T.S. 

%  D.V.S. 

%  D.L.S. 

in  cones 

7 

0.9 

18.0 

27.9 

149 

17.6 

5.3 

17 

72 

7.3 

16.4 

23.7 

133 

13.6 

4.4 

20 

122 

7.9 

22  2 

30.1 

110 

13.9 

4.5 

17-18 

131 

17.4 

22.8 

40.2 

9  4 

2  8.4 

8.6 

23-26 

171 

13.5 

24.6 

3  8.1 

-(-164 

20.9 

6.5 

198 

6.7 

18.9 

25.6 

166 

10.0 

3.2 

218 

12.9 

15.3 

28.2 

186 

24.3 

7.5 

23 

256 

16.8 
=  Per 

23.5 
cent  shrin] 

40.3 
kage  water. 

156 

27.7 

8.4 

19-20 

%  S.W. 

%P.W. 

%  W.P. 

=  Per 

cent  pore 

water. 

=  Per 

cent  water 

•  of  plasticit; 

V. 

D.T.S. 

=  Dry 

transverse 

strength,  pounds  per 

square  inch, 

without  sand 

%  D.V.S.   =  Dry 

ing  shrinkage,   per  cent 

dry  volu 

me. 

<%,D.L.S.    =  Calculated  linear  drying  shi 

finkage,  per  cent  dry 

length. 

*  Impure   flint  clay  from   Goat   Ranch,   Gladding,   McBean   &   Co.,    Orange   County, 
Description  of  ceramic  properties  omitted.     See  p.   141    for  description  of  deposit. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


331 


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332 


DIVISION  OF  MINES  AND  MINING 


010 


Absorption  and  linear  shrinkage  curves  for  clays  of  class  12. 
08  06  0^02  I    3  5    7    9  II   13  JS' 


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HEAT  TREATHEN  T  IN  CONES. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


333 


Absorption  anrl  lin<-;tr  shrinkago  curvis  for  clays  of  class  12. 


12 

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DIVISION  OF  MINES  AND  MINING 


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Ill-B.   Dense- Burning.     Less   Than    6%    Apparent    Porosity    at   Vitrification. 

a.  With  Loxo  Vitrificatiox  Raxge,  \  Cones  or  Moke. 

14.  Mainly  Medium  to  High  Strength,  But  Also  Including  Some  Clays 

of  Low  Strength. 

No.  10  (p.  163).  Riverside  County.  AlberhiU  C.  &  C.  Co.  "Hill  Blue 
Green."  Tliis  is  a  fine-grained,  exee.ssively-plastie  clay  that  serves 
mainly  as  a  strengthening  clay  in  sewer-pipe  and  similar  mixes.  The 
dry  strength  is  verv  high,  but  the  excessive  dr^dng  shrinkage  causes 
serious  warping  and  cracking  when  used  alone.  The  dry  clay  is  very 
hard  and  dense.  The  colors  are:  drv,  23"'"b;  wet,  21'"';  cones  010 
to  06,  9'b ;  cones  04  to  1,  9"  ;  cones  3  to  5,  9"' ;  cone  7.  1"' ;  cone  9,  l""b  ; 
cone  11,  13""d  (flashed).  All  test  ]iieces  cracked  on  firing,  except  those 
at  cones  010  and  08.  Finger-nail  hardness  is  found  in  the  dry  state, 
steel  hardness  is  developed  at  cone  04,  vitrification  is  complete  at  cone 
1,  and  bloating  begins  above  cone  5.  The  total  maximum  linear  shrink- 
age is  22.3'/  ,  at  cones  3  to  5.  The  softening  i)oint  is  cone  14-15.  The 
long  vitrification  range  and  excellent  dry  strength  of  this  clay  are  its 
princijial  merits. 

No.  21  (p.  163).  Riverside  County.  AlberhiU  C.  &  C.  Co.  "Sagger 
Clay."  This  is  a  pink-burning,  plastic  clay  that  finds  use  as  a  vitrifying 
agent  in  sagger  bodies.  It  has  a  smooth,  strong  ]ilasticity,  and  a  medium 
low  dry  strength.  There  is  slight  effervescence  in  hydrochloric  acid.  In 
the  dry  state  it  is  soft,  with  a  medium-fine  grain,  and  has  a  tendency 
to  laminate.  The  colors  are :  drv,  7"b ;  wet,  7"  ;  cones  010  to  04,  5'd ; 
cone  02,  7'd ;  cones  1  to  5,  7"d  ;"  cone  7,  13"'d;  cones  9  to  13,  17"'d. 
Iron  specks  are  prominent  at  cone  7  or  above.  Finger-nail  hardness  is 
developed  below  cone  010,  and  steel  hardness  at  cone  1.    A  few  small 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  335 

(Tiii'lss  appeared  in  the  test  iirin^i,  jji-obably  cau.sed  by  too  rapid  firing 
duriiiji-  tlu'  water-smokiiijr  stajie.  Tlie  total  linear  .slirinkajre,  plastic 
basis,  at  cone  }').  is  2\.-\' i  .  The  softening  point  is  cone  2."?.  The  best 
firing  i-ange  is  from  eone  02  to  cone  ^'^.  The  wide  vitrification  range  of 
this  eiay  within  tlie  limits  of  commercial  firing  is  its  principal  merit. 
With  the  addition  of  non-plastic  material,  it  is  suitable  for  pink-  and 
l)uft'-burned  face  brick,  roofing  tile,  and  similar  ])roduets,  as  well  as  for 
saggei-s. 

A'o.  ^^;?  (p.  163).  Riverside  County.  Alberhill  C.  &  C.  Co.  "Yellow 
Owl  Cut."  This  is  a  yellowish  clay  containing  12.6'/,  of  +2()()-mesli 
sai.J,  and  has  good  jjlasticity,  high  drying  shriidcage,  medium-high  dry 
strength,  and  good  dry  condition,  though  with  a  tendency  to  laminate.  It 
is  used  in  sewer-])i])e  mixes.  The  colors  are  :  drv,  15"d  ;  wet,  15"  ;  cones 
010  to  08,  5'd  ;  cones  06  to  0-1,  7'd  ;  cones  02  and  1,  9'b  ;  cones  3  to  7,  7"b  ; 
cones  9  to  13,  9""d.  Finger-nail  hardness  is  developed  at  cone  010,  and 
steel  hardness  at  cone  1.  The  total  linear  shrinkage,  plastic  basis,  is 
1H.6'(,  at  cone  11,  and  slight  bloating  a])i)ears  at  cone  13.  The  soften- 
ing i)oint  is  cone  17.  The  best  firing  i-ange  is  from  cone  02  to  cone  11. 
The  most  desirable  features  of  this  clay  are  its  dry  strength  and  wide 
vitrification  range. 

Xo.  75  (p.  174).  Riverside  County.  Alberhill.  L.  A.  B.  Co.  "Red 
Xo.  2."  This  is  a  vitrifying  clay  with  its  light-red  firing  colors  that  is 
valuable  in  roofing-tile  and  face-brick  mixtures.  In  the  natural  state 
it  is  hard  and  brittle  and  the  color  is  mottled  i)iidv  and  cream.  It  con- 
tains 16.4'>v  of  -(-200-mesh  sand.  The  plasticity  is  excellent,  the  dry 
strength  is  medium,  and  the  dried  condition  is  medium-hard,  and 
medium  close-grained.  The  colors  are:  drv,  7"b ;  wet,  7";  cones  010 
to  1,  9'b;  cones  3  to  9,  9"b ;  cones  11  and  13,  l""i  (flashed).  Finger- 
nail hardness  ai)pears  below  cone  010,  and  steel  hardness  at  eone  3. 
Absor])tions  below  lO'^  are  obtained  at  cone  5,  and  vitrification  is  com- 
l^lete  at  coiu^  11.  Slight  bloating  ap])ears  at  cone  13,  under  reducing 
conditions.  The  fired  test  pieces  are  moderately  hair-cracked,  and  at 
cones  11  and  13  a  few  large  open  cracks  appear.  The  maximum  total 
linear  firing  shrinkage,  ])lastic  basis,  is  24.0^^,  at  cone  11.  The  soften- 
ing point  is  cone  20-2)].  The  best  firing  range  is  from  cone  3  to  cone  11. 
The  clay  should  be  mixed  with  non-plastics  to  obtain  safe  firing 
l)roperties. 

No.  123  (p.  56).  Amador  County.  lone  (Carbondale).  Lea.sed  by 
G.  A.  Starkweather.  "Yaru  No.  2."  This  is  a  red-burning  clay  with 
smooth  and  weak  ])]asticity.  and  medium  dry  strength.  It  contains  5.4% 
of  -|-200-mesh  quartz-mica  sand.  In  the  dried  condition  it  is  soft,  fine- 
grained and  close-textured.  The  colors  are:  dry,  17"d ;  wet,  17"b; 
cones  010  to  7,  9' ;  cone  9,  9"" ;  cones  11  and  13,  T''\  Steel  hardness  is 
developed  at  cone  02.  Less  than  10%  absoi'])tion  a])pears  at  cone  1. 
The  fired  structure  is  sound,  and  the  texture  is  smootli.  Vitrification 
is  complete  at  cone  11,  and  blistering  a])i)ears  at  cone  13.  The  maximum 
total  shrinkage.  ])lastic  basis,  is  22.1%,  at  cone  11.  The  softening  j)oint 
is  cone  27-28.  The  best  firing  range  is  from  cone  1  to  cone  11.  The 
clay  may  be  used  for  face  brick,  roofing  tile,  red-burned  pottery,  etc. 

No.  127  (p.  57).  Amador  County.  lone.  M.  J.  Bacon.  "Bacon 
Red."      This  is  a  red-burning  clay  with  excellent  smooth  plasticity, 


336  DIVISION  OP  MINES  AND  MINING 

and  medium  low  dry  strenutli.  In  tlio  dried  condition  it  is  soft,  and 
fine-grained.  The  colors  are:  dry,  7"b;  wet,  7";  cones  010  to  5,  9'b; 
cone  7,  7'b ;  cones  9  to  11],  7"b.  Steel  hardness  appears  at  cone  1.  Less 
than  10%  absorption  is  obtained  at  cone  7.  The  fired  structure  is 
sound,  and  the  fired  surface  is  smooth.  Tlie  total  lineai-  shrinkage, 
plastic  basis,  at  cone  13,  is  20.0%.  The  softening  point  is  cone  27.  The 
best  firing  range  is  above  cone  1.  The  clay  may  be  used  for  face  brick 
and  roofing  tile,  and  for  pink  colored  pottery  or  tile  bodies. 

Xo.  148  (p.  156).  Placer  County.  Lincoln.  Lincoln  Clay  Products 
Co.  "No.  8."  This  is  a  red  burning  variety  that  possesses  nearly  the 
same  plastic,  drying  and  firing  i)roi)erties  as  No.  146,  in  class  8,  but 
with  a  lower  softening  ])oint.  It  contains  \2.V/v  of  -|-200-mesh  sand. 
It  is  used  for  face  brick,  sewer  pil)e,  roofing  tile,  etc.  The  colors  are: 
dry,  15'b  ;  wet,  15'b  ;  cones  010  to  04,  f/d  ;  cones  02  to  3,  7"b ;  cone  5,  7" ; 
cone  7,  7";  cone  9,  l'"i;  cones  11  and  13,  V".  Steel  hardness  develops 
at^cone  1.  Less  than  lO^^  absor|)tion  is  developed  at  cone  3.  The  fired 
structure  is  sound  and  stony.  Blistei'ing  is  noticeable  at  cone  11.  The 
maximum  total  linear  shrinkage,  plastic  basis,  is  20. 29^,  at  cone  9.  The 
softening  i)oint  is  cone  20.  The  best  firing  range  is  from  cone  1  to 
cone  9. 

No.  177  (j).  66).  Butte  County.  Oroville.  Quiney  road.  This  sam- 
ple contains  a  high  i)roi>ortion  of  partly-deeom])osed  volcanic  ash. 
Since  it  is  the  only  sami)le  of  its  type  on  which  test  data  could  be 
secured,  the  results  are  given  as  a  matter  of  general  interest.  The 
plasticity  is  weak  and  spongy,  the  dry  strength  is  medium-high,  and  in 
the  dried  condition  it  is  hard,  fine-gi-ained,  and  close-textured.  The 
colors  are  :  dry,  17"'f ;  wet,  17"i ;  cones  010  and  08,  15"d  ;  cone  06,  13'b ; 
cone  04,  13'd ;  cones  02  and  1,  17''i.  Steel  hardness  is  developed  at  cone 
04.  The  sharp  change  from  16.8%  porosity  at  cone  04  to  0.1%  porosity 
at  cone  02  should  be  especially  noted,  together  with  the  corresponding 
sharp  decrease  in  volume.  The  fired  structure  at  cone  02  is  glassy,  and 
large  cracks  are  present.  Bloating  and  fusion  follow  when  fired  above 
cone  1.     The  total  linear  shrinkage,  i)lastic  basis,  is  26.6%,  at  cone  1. 

No.  181  (p.  80).  Humboldt  County.  Angel  Ranch.  This  clay  has 
been  used  by  Mr.  R.  H.  Jenkins  at  the  Humboldt  State  Teachers  College, 
as  a  casting  clay  for  pottery.  It  has  good  ]ilasticity,  with  a  tendency  to 
stickiness.  The  residue  on  200-mesh  is  8.8'/*  .  The  dry  strengtli  is 
medium  high,  and  in  the  dried  condition  it  is  medium  hard,  fine-grained, 
and  close-textured.  The  colors  are:  drv,  17'"f;  wet,  17"'b ;  cone  010, 
ll'f;  cone  08,  ll'd ;  cones  06  and  04,  9"'d ;  cone  02,  ll'd;  cone  1,  9"i; 
cone  3,  ll"i;  cone  5,  15".  Steel  hardness  appears  at  cone  08,  and  less 
than  10%  absorption  at  cone  04.  Vitrification  is  complete  at  cone  1, 
and  a  vesicular  structure  is  developed  beyond  cone  1.  The  fired  struc- 
ture is  sound  and  stony,  and  the  surface  texture  is  smooth.  The  maxi- 
mum total  linear  shrinkage,  plastic  basis,  is  14.0%,  at  cone  1.  The  best 
firing  range  is  from  cone  08  to  cone  1. 

No.  188  (p.  92).  Lake  County.  Kelseyville.  This  is  a  red-burning 
thin-bedded  clay  shale.  The  clay  slakes  readil\'  in  water,  and  works 
into  a  smooth  and  moderately  strong  plasticity.  It  effervesces  slightly 
in  hydrochloric  acid.     The  thy  strength  is  medium,  and  in  the  dried 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  337 

eoiitlitioii  it  is  iiiodiuin  Jiard,  fine-fjraiiied,  and  close-textiirtMl.  The 
colors  are:  dry,  17'"f;  wet.  17"'i ;  oonc  010.  11";  eono  OS,  13";  cones 
06  lo  02,  })';  cones  1  and  3,  7"k.  Steel  liardness  is  developed  at  cone 
04,  and  less  than  10' r  absorption  at  cone  1.  The  fii-ed  strength  is 
medium  and  a  few  small  cracks  are  present  in  all  fired  test  pieces.  The 
total  linear  shrinkage,  plastic  basis,  is  25A%  at  cone  3.  On  account  of 
excessive  shrinkage,  sliort  vitrilication  range,  and  medium  strength,  this 
material  is  only  useful  for  manufacturing  a  poor  quality  of  common 
brick,  even  if  mixed  witli  non-plastic  material. 

No.  202  (p.  68).  Calaveras  County.  Valley  Sjirings.  California 
I'ottery  Co.  ''Pink  ^Mottled."  This  is  a  fine-grained,  red-burning  clay, 
with  smooth  and  strong  plasticity,  and  medium  dry  strength.  It  con- 
tains AA'/v  of  -|-200-mesli  santl.  In  the  di"ied  condition  it  is  soft,  fine- 
grained, and  clo.se-textured.  A  strong  tendency  to  laminate  was  noted. 
Tlie  colors  are:  dry,  11';  wet,  7'i ;  cones  010  to  04,  9"b;  cones  02  to  5, 
11" ;  cones  7  and  9,  9".  Steel  hardness  is  developed  at  cone  02,  and 
less  than  10%  absorption  at  cone  1.  The  fired  structure  is  sound, 
tough,  and  stony.  The  surface  texture  is  smooth.  The  maximum  total 
linear  shrinkage,  plastic  basis,  is  20.6%,  at  cone  11,  and  bloating  is 
apparent  at  cone  13.  The  .softening  point  is  cone  20.  This  is  an  excel- 
lent face  brick  and  roofing  tile  clay. 

No.  203  (p.  68).  Calaveras  County.  Valley  Springs.  California 
Pottery  Co.  "Yellow  Plastic."  This  is  similar  in  its  ceramic  prop- 
ci-ties  to  Xo.  202,  but  is  not  so  fine-grained,  and  contains  more  non- 
plastic  matter.  The  residue  on  200-mesh  is  10.2%.  The  colors  are: 
dry,  ir)"b;  wet,  15"b;  cones  010  to  04,  ll'b;  cone  02,  9';  cones  1  to  o, 
11";  cone  7,  7";  cone  9,  5".  Steel  hardness  is  developed  at  cone  1,  and 
less  than  10%  absorption  at  cone  5.  The  surface  texture  is  rougher 
than  that  of  No.  202.  The  total  linear  shrinkage,  plastic  basis,  is 
18.0%,  at  cone  13.    The  softening  point  is  cone  19-20. 

No.  210  and  212  (j).  186).  Sacramento  County.  Xatoma.  Xo.  210 
is  a  sample  of  ''Xatoma  Xo.  1,"  and  Xo.  212  is  a  sample  of  "Xatoma 
No.  3."  They  differ  onl}'  in  the  proportion  of  non-plastic  matter,  which 
is  greater  in  X"o.  212  than  in  X'^o.  210.  The  clay  is  extremely  fine- 
grained, and  contains  a  high  i)roportion  of  mica.  The  jilasticity 
is  strong,  and  in  the  dried  condition  the  samples  have  finger-nail 
hardness,  are  fine-grained,  and  close-textured.  The  clay  must  be 
dried  carefully  to  avoid  cracking.  The  dry  strength  of  Xo.  210  is 
high,  and  of  Xo.  212  is  medium  liigh.  The  colors  of  Xo.  210  are:  dry, 
13"b;  wet,  13"i;  cones  010  to  04,  9';  cone  02,  9'i;  cones  1  and  3,  9k; 
cone  5,  9'm.  The  colors  of  X^^o.  212  are:  dry,  13'';  wet,  11";  cones 
010  to  06,  13" ;  cone  04,  7" ;  cones  02  to  3,  7"i ;  cone  6,  5"m.  Steel  hard- 
ness and  less  than  10%  absorption  are  developed  at  cone  04,  and  vitrifi- 
cation is  complete  at  cone  5.  A  vesicular  structure  appears  at  cones  7 
to  9.  The  fired  structure  is  sound  and  strong  and  the  .surface  texture 
is  smooth.  The  total  linear  shrinkage,  plastic  basis,  of  No.  210  is  19.1%, 
at  cone  5,  and  of  X'^o.  212  is  16.9%,  at  cone  6. 

Mr.  L.  W.  Austin,  of  the  company,  kindly  gave  the  following  data 
on  Xo.  210 : 

22—54979 


Equivalent 

Acciinnil 

Si/.v  in  imn. 

mesh 

on 

0.02 

1.000 

0.40 

0.01 

2,000 

2. OS 

O.OOU 

3,000 

7.0G 

(1.(104 

4,000 

13.36 

o.oo:! 

5,000 

20.19 

0.002 

10,000 

29.89 

0.001 

20,000 

52.07 

0.000(1 

30,000 

59.22 

338  DTVTRTON  OF  MINES  AND  MINTNfi 

Sizing  Test  of   Natoma   Clay  No.   1. 

{{\\v  Percent 

through 

99.60 
97.97 
92.94 
86.64 
79.81 
70.11 
47.93 
40.78 

]\ri'.  Austin  ro])orts  the  results  of  commercial  firiiio'  tests  on  Natoma 
No.  1  (our  number  210)  as  follows:  Drying  shrinkage,  7.5  to  9.0%; 
total  linear  firing  shrinkage  at  cone  5,  approximately  15%  ;  absorption 
at  cones  5  to  7,  0.35  to  0.1%  ;  bloating  usually  begins  at  cone  9.  Another 
firing  test  gave  a  total  linear  shrinkage,  plastic  basis,  of  20. 5^^,  after 
heating  to  cone  5  in  36  hours  and  holding  the  finishing  temperature 
for  4  hours. 

A  number  of  clay  products  manufacturers  have  tested  this  clay,  and 
some  have  introduced  it  into  their  mixes.  It  is  particularly  valuable 
for  the  purpose  of  producing  a  hard,  strong  vitrified  body,  with  rich- 
red  colors,  and  a  smooth  texture.  In  some  plants  the  sviccessful  use  of 
this  clay  will  require  a  modification  of  the  drying  procedure.  The 
clay  can  be  cast,  or  pressed,  and  takes  die  impressions  very  perfectly. 
In  an  auger  machine,  the  finely  divided  mica  is  an  aid  to  lubrication, 
yet  the  flakes  are  not  so  large  as  to  cause  excessive  lamination. 

b.  With  Short  Vitrification  Range,  Less  Than  4  Cones. 
15.     Medium  to  High  Strength. 

No.  1  (p.  218).  Santa  Barbara  County.  R.  Muengenberg  and  E. 
11.  Whitiker.  West  Montecito  Street,  Santa  Barbara.  This  is  a  mixture 
of  a  yellowish  sandy  clay  and  a  plastic  black  adobe,  mined  locally  and 
used  for  structural  wares.  It  effervesces  .slightly  in  hydrochloric  acid. 
It  develops  a  sticky  plasticity  and  has  high  dry  strength  and  good  dry 
structure.  The  percentage  of  -f--^^0-i^i<^^li  sand  is  33.2.  The  dry  color 
is  17"",  the  Avet  color  is  17""i,  and  the  fired  color  to  cone  3  is  9'i,  a 
good  color  for  common  brick.  Steel  hardness  is  developed  at  cone  1, 
and  bloating  appears  at  cone  5.  The  maximum  total  linear  shrinkage, 
plastic  basis,  is  12.8%  at  cone  3.  The  best  firing  range  is  from  cone 
02  to  cone  3. 

No.  2  (p.  218).  Santa  Barbara  County.  Toro  Canyon,  near  ]\Ionte- 
cito.  An  adobe  clay,  used  in  the  Toro  Canyon  brickyard  operated  by 
jMuengenberg  and  Whitiker  for  the  manufacture  of  red  structural 
wares.  The  percentage  of  -|-200-mesh  sand  is  33.4.  It  develops  a  sticky 
plasticity  and  high  dry  strength  with  good  (\vx  structure.  The  dry 
color  is  13"'  and  the  wet  color  is  13'"i.  The  fired  color  is  9'i  from 
cones  010  to  02,  and  7"i  from  cones  1  to  3,  both  of  which  are  good 
common  brick  colors.  Steel  hardness  is  developed  at  cone  1,  and 
bloating  appears  at  cone  5.  The  maximum  total  linear  shrinkage, 
plastic  basis,  is  12.5%  at  cone  3.  The  best  firing  range  is  between  cones 
02  and  3. 

No.  4  (p  234).  Ventura  County.  A  yellow  plastic  clay  from  the  Fer- 
nando (Pliocene)  formation,  north  of  Ventura,  and  used  by  the  People's 


CLAY  RESOURCES  AXD  CERAMIC  INDUSTRY  339 

LuiiilxT  Co.  for  tlio  mamit'aeture  of  ml  si  i-iirliii;il  ware.  It  is  finc- 
^raiii(>(l.  and  <l('V('l()|)s  sticky  plasticity  and  liiiili  di-y  strcii<:tii,  l)ul  lias 
a  lii^^h  dryiiiji'  slirinka<.;c  and  a  tendency  to  warp  wiien  nscd  alone.  It 
contains  hut  lA'/c  of  +2()()-mesli  sand".  The  dry  color  is  17"'b,  the 
wot  color  is  17'",  and  liie  tired  colors  are  i)'I)  from  cones  010  to  06,  9' 
at  cone  04,  and  !)'i  fi'oin  cones  02  to  1,  <;ivin<;'  an  excellent  i-anjre  for 
conuuon  brick,  building'  tile,  and  roofing  tile.  Steel  hardness  is 
developed  at  cone  02,  and  bloating  begins  above  cone  1.  The  maximum 
total  linear  shrinkage,  plastic  basis,  is  21.4%,  at  cone  1.  The  best  firing 
range  is  from  cone  04  to  cone  1.  The  high  shi-inkage  should  be 
reduced  with  non-i)lastic  material  for  best  results  in  nuiking  .structural 
ware. 

No.  .-)  (|).  234).  Ventura  County.  A  grayish  blue  plastic  clay  over- 
lying No.  4.  Used  principally  for  oil-well  mudding,  and  with  clay 
Xo.  4  in  the  manufacture  of  structural  ware.  The  ceramic  ])roperties 
are  similar  to  those  of  sample  Xo.  4.  The  dry  color  is  21""b,  the  wet 
color  is  21"",  and  the  fired  colors  are  7"b  from  cone  010  to  cone  04, 
.I'd  at  cone  02,  7"  at  cone  1,  and  13"'i  (flashed)  at  cone  3.  Knife 
hardness  is  develoi)ed  at  cone  02,  maximum  shrinkage  at  cone  1,  and 
bloating  begins  near  cone  3.  The  maximum  total  linear  shrinkage, 
plastic  basis,  is  20.0%,  at  cone  1.  The  best  firing  range  is  from  cone  04 
to  cone  1.  For  best  results,  the  clay  should  be  mixed  witii  non-plastic 
material  for  manufacturing  structural  ware. 

No.  6  (p.  234).  Ventura  County,  2.7  miles  north  of  Santa  Paula.  A 
yellowish  plastic  clay  used  for  making  dry-pressed  common  brick  in 
the  yard  of  Anderson  and  llardison.  Jt  contains  17.8 y^  of  -[-200-mesh 
sand  and  develops  good,  but  sticky,  plasticity,  and  high  dry  strength. 
Tiiere  is  slight  effervescence  in  hydrochloric  acid.  The  dry  color  is 
17"'b,  the  wet  color  is  17"'i,  and  tlie  fired  colors  are  7'b  from  cone 
010  to  cone  02,  7"  at  cone  1,  and  7"i  (flashed)  at  cone  3.  These  are 
good  red  brick  colors.  Knife  hardness  is  developed  at  cone  02,  and 
slight  bloating  is  apparent  at  cone  3.  The  maximum  total  shrinkage, 
plastic  basis,  is  17.5 /V ,  at  cone  1.  The  best  firing  range  is  from  cone 
04  to  cone  1-|-.  The  wide  vitrification  range,  from  cone  02  to  cone  3 — , 
coupled  with  other  desirable  (lualities,  make  this  a  good  clay  for  hard 
burned  structural  w^are. 

No.  30  (p.  203).  San  Diego  County.  Rose  Canyon.  San  Diego  Tile 
and  Brick  Co.  This  is  a  vellow  and  grav  Tertiarv  clav  shale,  used  for 
making  common  brick  and  hollow  building  tile.  It  effervesces  slightly 
in  hydrocldoric  acid.  It  contains  lii.O'r  of  -|-200-mesh  sand,  has  good 
plasticity  for  either  the  auger  or  the  brick-press,  medium  high  dry 
strength,  and  a  good  dry  structure.  It  can  be  dried  rapidly  without 
danger  of  cracking.  The  colors  are:  drv,  21"";  Avet,  17"";  cones  010 
to  04,  9'd;  cones  02  and  1,  9";  cone  3,' 9"' ;  cone  5,  9"'i.  The  fired 
colors  cover  a  good  range  of  desirable  common  brick  reds.  Finger-nail 
hardness  is  present  in  the  dry  state,  and  knife  hardness  appears  at 
cone  1.  Vitrification  is  complete  at  cone  3,  and  bloating  begins  at 
cone  5.  The  fired  brick  are  hard,  dense  and  sound.  The  maximum 
total  linear  shrinkage,  plastic  basis,  is  16.4%,  at  cone  3.  The  best  firing 
range  is  from  cone  010  to  cone  3,  and  excellent  hard-burned  brick  are 
obtained  from  cone  1  to  cone  3. 


340  DIVISION  OP  MINES  AND  MINING 

No.  o/  ()).  204).  San  Die«ro  County.  Rose  Canyon.  Union  Brick  Co. 
An  unconsolidated  j^elloAvisli  sandy-clay  of  Tertiary  a«:e.  The  forma- 
tion contains  pcbhles  and  bonldors,  the  larprer  part  of  Avhicli  are  removed 
by  screening.  The  sample  contains  :>2.(i',  of  -]-200-mesh  sand.  It  is 
used  for  common  brick,  but  is  suitable  also  for  making  liollow  building 
tile.  The  plastic  and  drj^ing  properties  are  such  that  it  can  be  used 
alone.  It  has  a  higli  dry  strength,  and  in  the  dry  state  it  is  hard,  with 
a  medium  grain  and  open  texture.  The  colors  are:  dry,  17'"b;  wet, 
13'"i ;  cones  010  to  02,  9'i ;  cones  1  and  3,  7" ;  cone  5,  9''i.  These  are 
nearly  the  same  as  in  sample  No.  30,  and  cover  a  good  range  of  common 
brick  colors.  Finger-nail  hardness  is  present  in  the  dry  state,  and  steel 
hai'dness  appears  at  cone  1.  Vitrification  is  complete  at  cone  3,  and 
l)loating  appears  at  cone  5.  The  maximum  total  linear  shrinkage  is 
10.4%  at  cone  3.  The  best  firing  range  is  from  cone  010  to  cone  3,  and 
Avell  vitrified  products  are  obtained  from  cone  1  to  cone  3. 

No.  42  (p.  181).  San  Bernardino  County.  Vidal.  "Blue."  See  also 
No.  43.  This  is  a  bluish,  extremely  fine-grained  clay-shale  of  the  ben- 
tonitic  type.  In  water,  it  slakes  readily  to  a  smooth  slip.  It  effervesces 
strongly  in  hydrochloric  acid.  When  mixed  with  57.7%  water,  it  devel- 
ops a  smooth,  workable  plasticity,  without  excessive  stickiness.  The 
drying  shrinkage  is  high,  and  ordinary  air-drying  methods  caused 
large  drying  cracks  and  excessive  warping  to  develop.  In  the  dried 
state,  it  is  hard,  fine-grained,  brittle  and  close-textured.  The  dry 
strength  could  not  be  determined  accurately.  With  the  firing  schedule 
emplo.yed,  the  clay  was  badly  shattered,  but  data  were  obtained  for 
cone  010  and  cone  08.  The  colors  are:  dry,  17"'f;  wet,  21'"d;  cones 
010  and  08,  15"b.  Finger-nail  hardness  appears  in  the  dry  state,  and 
steel  hardness  at  cone  010.  In  view  of  the  isolation  of  the  deposit,  it 
has  no  commercial  A'alue.  The  fineness  of  grain,  plastic  strength,  and 
apparently  high  dry  strength  are  interesting  features.  No  tabulated 
data  or  charts  of  firing  shrinkage  and  absorption  are  presented. 

i\^o.  45  (p.  181).  San  Bernardino  County.  Vidal.  "Pink."  This 
clay  is  similar  to  No.  42,  except  that  it  contains  more  iron  and  more 
non-plastic  matter,  resulting  in  deeper  fired  colors,  and  lower  drying 
and  firing  shrinkage.  It  effervesces  strongly  in  hydrochloric  acid. 
The  dry  strength  is  high.  The  colors  are:  dry,  ll'f ;  wet,  17""d;  cones 
010  to  1,  11";  cone  3,  13"k.  Efflorescence  is  especially  pronounced. 
Finger-nail  hardness  is  present  in  the  dried  state,  and  steel  hardness  is 
developed  at  cone  OS.  At  cone  3,  kiln-marking  and  bloating  begins. 
The  maximum  total  linear  shrinkage,  plastic  basis,  is  20.0%,  at  cone  1. 
The  fired  structure  is  tough  and  strong.  The  best  firing  range  is  from 
cone  08  to  cone  1. 

No.  60  (]).  100).  Los  Angeles  County.  Los  Angeles.  Davidson  Brick 
Co.  This  is  a  red-burning  clay  suitable  for  the  manufacture  of  com- 
mon structural  ware.  The  ratio  of  clay  to  sand  is  such  that  the  plas- 
ticity, drying  and  firing  properties  are  entirely  satisfactory  without 
admixture  with  other  materials.  It  contains  5.4%,  of  +200-mesh  sand. 
There  is  slight  effervescence  in  hydrochloric  acid.  The  dry  strength  is 
medium-high,  and  the  dry  structure  is  hard,  fine-grained,  and  open- 
textured,  with  a  tendency  to  laminate.    The  colors  are :  Avy,  17"d ;  wet, 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  341 

]7'"i  •  cone  010  9'(1 ;  cone  08,  ll'b ;  cone  OG,  U'b ;  cone  04,  9"b ;  cone  02, 
!"•  cone  1,  9"';  cone  3,  5'"i ;  and  cone  5  (bloated)  9"'k.  This  affords 
an 'excellent  range  for  red  brick.  Finger-nail  hardness  is  obtained 
below  cone  010,  and  steel  hardness  develops  at  cone  1.  Vitrification 
is  complete  at  cone  3.  and  bloating  begins  just  below  cone  5.  All  fired 
test  pieces  were  sound  and  strong.  Tiie  maximiiin  total  linear  shrink- 
age, plastic  basis,  is  I6.97; ,  at  cone  3.  Tlie  best  firing  range  is  from 
cone  010  to  cone  3,  or  if  vitrified  products  are  desired,  from  cone  1  to 
cone  3. 

Xo.  61  (p.  102).  Los  Angeles  County.  Santa  :Monica.  (Jladding, 
McBean  and  Co.  This  is  representative  of  tlie  clay  used,  by  several 
other  plants  in  the  same  locality,  and  in  some  of  the  sewer-pipe  and 
conduit  plants  in  the  Los  Angeles  district.  It  is  a  red-burning  clay, 
witli  suitable  plastic,  drying,  and  firing  properties  to  permit  its  use 
as  the  sole  ingredient  of  common  brick,  hollow  building  tile,  roofing 
tile,  etc.,  and  as  a  vitrifving  and  bonding  clay  in  sewer-pipe  and  elec- 
trical conduit  mixes.  It  contains  18.07o  of  -f  200-mesh  sand.  The  dry 
.strength  is  medium  liiu'h.  and  the  dry  condition  is  hard,  fine-grained, 
and  close-textured.  Tlie  colors  are:  dry,  17"';  wet  13''"k;  cone  010, 
ll'b:  cone  08,  11' ;  cones  06  and  04,  9' ;  cone  02,  9'i;  and  cones  1  and  3, 
9"k.  These  colors  give  a  suitable  range  for  the  uses  indicated  above. 
Finger-nail  hardness  is  obtained  below  cone  010.  and  steel  hardness  at 
cone  02.  Vitrification  is  complete  at  cone  1,  and  bloating  begins  at  cone 
3.  The  fired  structure  is  sound  and  strong.  The  maximum  total  linear 
shrinkage,  plastic  basis,  is  13.1 7r,  at  cone  1.  The  best  firing  range  is 
from  cone  010  to  cone  1,  or  if  vitrified  products  are  desired,  from  cone 
02  to  cone  3. 

.V^;.  89.  Riverside  County.  Elsinore.  Hudson  Ranch  clay.  This 
is  a  red-burning  sandy  clay  from  an  undeveloi:)ed  deposit.  It  effervesces 
slightly  in  hydrocliloric  acid.  It  has  good  plasticity,  medium-high  dry 
strength,  and  the  dried  condition  is  hard,  medium  fine-grained,  and 
close-'textured.  The  colors  are:  dry,  17""b;  wet,  17"";  cones  010  to 
06,  15"b;  cones  04  to  1,  13"b ;  cones  3  and  5,  7'';  cones  7  to  13,  7"k. 
Finger-nail  hardness  is  present  in  the  dried  state,  and  steel  hardness 
is  developed  at  cone  7.  Ab.sorptions  under  lO^r  are  obtained  at  cone 
11,  and  bloating  is  well  developed  at  cone  13.  All  fired  test  pieces  are 
sound.  The  maximum  total  linear  shrinkage,  plastic  basis,  is  20.2%  at 
cone  11.  The  clay  might  have  local  use  as  a  coloring  and  bonding  clay, 
but  its  high  shrinkage  and  short  vitrification  range  are  undesirable 
features. 

No.  118  (p.  192).  San  Benito  County.  Paicines.  This  is  a  yelloAvish, 
plastic  surface  clay,  with  a  smooth,  strong  ])lasticity  and  exceptionally 
high  dry  strength!  There  is  slight  effervescence  in  hydrochloric  acid. 
Tn^the  dried  condition  it  is  hard,  fine  grained,  and  close  textured.  It 
contains  4.0^;  of  -l-200-mesh  sand.  The  colors  are:  dry,  21""d ;  wet, 
21"";  cone  010,  9'd  :  coups  OS  and  06,  9'b;  cone  04,  9';  cones  02  and  1, 
9'k;  cone  3,  7"k.  Finger-nail  hardness  is  develoi^ed  below  cone  010, 
and  steel  hardness  at  cone  04.  Less  than  10%  absorption  is  developed 
at  cone  04,  and  vitrification  is  complete  at  cone  02,  above  which  temper- 
ature bloating  begins.  The  fired  structure,  up  to  cone  02,  is  sound  and 
stony.    The  maximum  total  linear  shrinkage,  plastic  basis,  is  18.8%,  at 


342  DIVISION  OF  MINES  AND  MINING 

cone  02.    This  clay  is  not  in  use,  but  would  be  entirely  suitable  for  red- 
burned  structural  ware,  and  is  worthy  of  investigation  as  a  casting  clay. 

No.  172  (}).  136).  Nevada  County.  ]\Ianzanita  ]Mine,  near  Nevada 
City.  This  is  the  so-called  "pipe  clay"  of  the  hydraulic  mines.  It 
develops  fair  plasticity,  medium-high  dry  strength,  and  a  medium-hard, 
fine-grained  and  open-textured  dried  condition.  The  colors  are:  dry, 
grayish  white;  wet,  28'""d;  cones  010  to  04,  15"b;  cones  02  to  3,  ll"b; 
cone  5,  5"i ;  cone  7,  5"k.  Steel  hardness  is  developed  at  cone  04,  and 
less  than  10*^^  absorption  at  cone  02.  The  fired  structure  is  sound  and 
stony,  and  the  surface  texture  is  slightly  rough.  Tlie  nuiximum  total 
linear  slirinkage,  plastic  basis,  is  24.8%  at  cone  5.  Bloating  is  apparent 
at  cone  7.  The  clay  could  be  mixed  with  non-plastics  and  used  locally 
for  the  manufacture  of  common  brick. 

No.  184  (p.  80).  Humboldt  County.  Eureka.  Freshwater  Slough. 
This  is  a  common  clay  with  good  plasticity,  and  medium  high  dry 
strength.  In  the  dried  condition  it  has  finger-nail  hardness,  is  fine- 
grained, and  close  textured.  The  colors  are:  drv,  17""b;  wet,  17""i ; 
cones  010  to  06,  13'b ;  cones  04  and  02.  ll'b;  cone  1,  13'k.  Steel  hard- 
ness is  developed  at  cone  04,  and  less  than  10'  {  absorption  at  cone  02. 
Vitrification  is  complete  at  cone  1.  The  fired  structure  is  sound,  and 
the  surface  texture  is  smooth.  The  maximum  total  linear  shrinkage, 
plastic  basis,  is  22.8%  ,  at  cone  1.  The  clay  is  entirely  suitable  for  the 
manufacture  of  common  brick,  hollow  tile,  and  roofing  tile,  but  should 
be  mixed  with  non-plastic  material  to  decrease  the  shrinkage. 

.Vo.  i(95  (p.  80).  Humboldt  County.  Eureka.  Loofbourrow  Ranch. 
This  is  a  common  clay  with  sticky  plasticity,  and  medium-high  dry 
strength.  It  is  extremely  fine-grained  and  contains  carbonaceous 
matter.  In  the  dried  condition  it  has  finsier-nail  hardness.  The  colors 
are;  dry,  15'""b ;  wet,  15'""i;  cones  010  to  04,  ll"b;  cone  02,  .5"; 
cone  1,  7"m.  Steel  hardness  and  less  than  10%  absorption  are  devel- 
oped at  cone  02,  and  vitrification  is  complete  at  cone  1.  The  fired 
structure  is  sound.  The  total  linear  .shrinkage,  plastic  basis,  is  19.3%, 
at  cone  1. 

No.  200  (p.  73).  Contra  Co.sta  County.  Walnut  Creek  (Oxley 
siding).  N.  Clark  &  Sons.  This  is  a  red-burning,  calcareous  shale 
that  is  used  as  a  non-plastic  ingredient  in  sewer-pipe  mixtures.  The 
plasticity  is  weak,  the  dry  strength  is  medium,  and  in  the  dried  condi- 
tion it  is  medium  hard,  fine-grained,  and  open-textured.  The  colors 
are:  dry,  17"'f;  wet,  17"'b;  cones  010  and  08,  15"b ;  cone  06,  11'; 
cones  04  and  02,  9';  cone  1,  9'k;  cones  3  and  5,  ll'ni.  Steel  hardness 
and  less  than  10"^;  absorjition  are  developed  at  cone  1.  The  fired 
structure  is  fine-granular,  and  the  surface  texture  is  slightly  rough. 
Above  cone  1,  the  test  pieces  are  disrupted  by  one  or  more  large  cracks, 
and  the  greenish-broAvn  coloration  due  to  the  presence  of  lime  is 
a])parent.  Tlie  maximum  total  linear  shrinkage,  ])la.stic  basis,  is  19.7%, 
at  cone  3. 

No.  211  ()).  81).  lliiiiil)()ldt  Comity.  Near  Strong's  Station,  Van 
Duzen  River.  This  is  a  common-l)rick  clay  tliat  has  good  pla.sticity, 
medium-high  dry  strength,  and  in  tlie  dried  condition  has  finger-nail 
hardness,   is   fine-grained,   and    close-textured.      The   colors   are :    dry. 


t'LAY  RESOUKCES  AXD  t'EHA.MR'   INDUSTRY  343 

21""d;  wet,  21""b;  cones  010  and  08,  13"b;  cones  06  to  02,  11";  cones 

1  and  3,  5"".  Steel  liardncss  and  less  Hum  lO'r  absorj^tion  a|>]iear  at 
cone  1.  The  fired  strncture  is  sound  and  stronj>',  and  the  surl'ace  texture 
is  slig:htly  roufrli.  The  total  linear  shrinkage,  plastic  basis,  is  15.1%, 
at  cone  3.  The  material  could  be  successfully  used  for  the  manufacture 
of  common  bi-iek  and  hollow  tile,  although  the  fired  colors  are  not 
especially  atti'active. 

No.  223  (p.  141).  Oranue  ("ounly.  ({oat  Ranch.  (J.,  McP..  tk  Co. 
Red-burning  -shale.  Tliis  material  develops  good  plasticity  if  ])roi)erly 
ground  and  jiugged.  The  dry  strength  is  medium-high,  and  in  tlie 
dried  condition  it  lias  finger-nail  li;ii-dness,  and  is  close-textured. 
Tlu're  is  sliglit  effervescence  in  livdrocldoric  acid.  The  colors  are:  dry, 
ir/'d;  wet,  17"k;  cones  010  to  06,  13"b;  cones  04  and  02,  11";  cone  1, 
o"\;  cone  3,  5"k  ;  and  cone  7.  y'm.  Steel  liardness  and  less  than  10% 
absor])tion  are  developed  at  cone  1,  and  bloating  a])i)ears  at  cone  5. 
Tlie  fired  structure  is  sound  and  strong.  Tlie  maximum  total  linear 
slirinkage,  plastic  basis,  is  lA.b'/c,  at  cone  3.  This  is  an  excellent 
material  for  the  manufacture  of  vitrified  heavy  clay  products,  such  as 
sewer  pipe,  electrical  coiuluit,  paving-  brick,  and  similar  ware. 

No.264{]).A2).  Alameda  County.  Decoto.  M  &  S  Tile  Co.  This 
is  a  common  alluvial  clay  that  is  used  for  making  hand-made  roofing 
tile.  The  plasticity  is  good,  the  dry  strength  is  high,  and  in  the  dried 
condition  it  has  finger-nail  hardness,  is  fine-grained,  and  close-textured. 
The  colors  are:  dry,  17"i ;  wet,  15"k ;  cones  010  and  08,  11';  cones  06 
and  04,  9'i ;  cone  02,  7'k.  Steel  hardness  and  less  than  10'/  absori)tion 
are  developed  at  cone  02.  Bloating  begins  above  cone  1.  The  fired 
structure  is  sound,  and  the  surface  texture  is  smooth.  The  total  linear 
shrinkage,  plastic  basis,  is  14.27' ,  at  cone  02.  This  clay  belongs  to  the 
same  geologic  formation  as  No.  265,  and  its  ceramic  pro])erties  are 
closely  similar. 

No.  265  (p.  40).  Alameda  County.  Niles.  W.  S.  Dickey  Clay  Manu- 
facturing Comi)any,  Plant  No.  18.  This  is  a  common  alluvial  clay  that 
is  used  for  manufacturing  hollow  tile  and  paving  brick.  The  i)lasticity 
is  fair,  but  it  is  usually  necessary  to  add  from  15  to  20^  of  a  ])lastic 
clay  from  Lincoln  or  lone  to  secure  suitable  working  i)roperties  for  an 
auger  machine.  The  dry  strength  is  medium  high,  and  in  the  dried 
condition  it  is  hard,  fine-grained,  and  close-textured.  The  colors  are: 
dry,  15"i ;  wet,  13"k;  cones  010  and  08,  IT  ;  cones  06  and  04,  9'i;  cones 

02  and  1,  9'm.  Steel  hardness  and  less  than  lO^'  absorption  are 
develojied  at  cone  02,  and  vitrification  is  complete  at  cone  1.  The  fired 
structure  is  sound  and  strong.  The  total  linear  shrinkage,  plastic  basis, 
is  14.0%,  at  cone  1. 


344 


DIVISION  OF  MINES  AND  MINING 


TABLE   No.  26. 

III.    Red-Burning   Clays. 

B.   Dense-burning-.      Less  than   6%  apparent  porosity  ;it  \itrificatiun. 

a.   With  long  vitrififation  i-ange,   4  cones  or  more. 

14.   Mainly  medium  to  high  strength,   but  also   including  some  clays  of  low  strength. 


Soften- 

Clay 

ing  pt. 

No. 

%  S.W. 

%  P.W. 

%  W.P. 

D.T.S. 

%  D.V.S. 

%  D.L.S. 

In  cones 

10 

3G.0 

10.5 

46.5 

1530-1- 

73.4 

20.0 

14-15 

21 

13.5 

21.7 

35.2 

187' 

23.3 

7.2 

23 

22 

23.5 

14.8 

38.3 

525 

45.0 

13.0 

17 

75 

16.6 

21.7 

38.3 

292 

28.7 

8.7 

20-23 

123 

19.2 

23.2 

42.4 

228 

31.0 

9.4 

27-28 

127 

16.9 

20.7 

37.6 

121 

28.8 

8.7 

27 

148 

15.9 

19.3 

35.2 

255 

28.1 

8.6 

20 

177 

22.1 

39.7 

61.8 

582 

26.4 

8.1 

181 

14.2 

12.3 

26.5 

794 

28.6 

8.6 

188 

25.1 

31.7 

56.8 

364 

36.2 

10.8 

202 

17.5 

21.5 

39.0 

230 

29.4 

8.9 

20 

203 

15.3 

18.6 

33.9 

232 

27.1 

8.2 

19-20 

210 

21.5 

15.5 

37.0 

1009 

40.3 

12.0 

212 

18.9 

16.3 

35.2 

625 

35.0 

10.5 

h.   With   short   vitrification   range,   less   tlian    4   coni's. 
15.   Medium   to  liig-h   strength. 


Soften- 

(May 

ing  pt. 

No. 

%  S.W 

%  PW. 

%  W.P. 

D.T.S.         (A 

D.V.S. 

%  D.L.S. 

in  cones 

1 

14.0 

13.1 

27.1 

848 

27.8 

8.5 

2 

12.0 

11.9 

23.9 

845 

24.4 

7.6 

4 

29.4 

17.8 

47.2 

1212 

54.0 

15.5 

5 

22.1 

18.3 

40.4 

]0;!4 

39.7 

11.8 

6 

22.2 

13.7 

35.9 

1258 

43.5 

12.8 

30 

15.3 

19.5 

34.8 

595 

27.3 

8.0 

31 

6.4 

13.5 

19.9 

903 

12.5 

4.0 

43 

30.4 

16.7 

42.7 

1158 

59.4 

16.8 

60 

14.2 

18.7 

32.9 

720 

25.1 

7.8 

61 

11.4 

14.2 

25.6 

639 

22.0 

6.9 

89 

27.5 

13.9 

41.4 

597 

52.4 

15.0 

118 

26.4 

13.1 

39.5 

1363 

53.2 

15.3 

172 

16.6 

41.0 

57.6 

352 

20.0 

6.3 

184 

26.4 

20.9 

47.3 

703 

43.8 

12.9 

185 

18.7 

21.4 

40.1 

502 

31.2 

9.4 

200 

14.7 

2  8. 3 

43.0 

363 

21.8 

6.9 

211 

14.2 

16.5 

30.7 

619 

26.1 

S.O 

223 

10.2 

16.8 

27.0 

412 

18.5 

5.8 

264 

15.6 

10.8 

26.4 

1020 

31.8 

9.6 

265 

12.5 

Per 

12.4 
cent  shrill 

24.9 
kage  water. 

791 

25.2 

7.8 

% 

S.W. 

% 

P.W 

i^ 

Per 

cent  pore 

water. 

W.P 

== 

Per 

cent  water  of 

plasticity 

D.T.S. 

=r 

Dry 

transverse 

Stl 

ength,  pounds  per  square  incli 

williout  sand. 

%  D.V.S.   = 

Dry 

ing  shrinkage, 

per  cent 

dry  volume. 

%  D.L.S. 


CLAY  RESOURCES  AND  CERAMIC  INDT'STRY 


345 


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346 


DIVISION  OF  MINES  AND  MINING 


Absorption  and  linear  shrinkage  curves  for  clays  of  class  14. 


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HEAT  TREATMENT  IN  CONES. 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


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348 


DIVISION  OP  MINES  AND  MINING 


Absurption  and  linear  shrinkage  curves  for  olays  of  class  15. 
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IV.  CLAYS    BURNING    DIRTY   WHITE,   CREAM    WHITE,   OR   YELLOWISH 

WHITE. 

17.  Generally  Contain  Calcium  or  Magne.sinm  Carbonate  or  Both,  and 
Seldom  Reach  Low  Porosity.    Very  Short  Firing  R;inge. 

No.  3  (p.  218).  Santa  Barbara  County.  One  mile  south  of  Carpinteria. 
Formerly  used  for  making  light-colored  common  brick  and  building 
tile,  in  the  Carpinteria  plant  of  the  Santa  Barbara  Builders'  Supply  Co. 
A  light-yellowish  sandy-shale,  which  develops  a  Aveak  and  sticky 
l)la.sticity,  but  with  medium-high  dry  strength.  The  deposit  contains 
lime  concretions  Avliich  Avere  sorted  out  as  much  as  possible,  but  the 
sam])le  contains  too  much  lime  for  satisfactory  testing,  as  all  test  pieces 
fired  below  cone  04  slaked  in  air  after  firing.  The  dry  color  is  17'"d,  the 
Avet  color  is  17'"b,  and  the  fired  colors  range  from  9'f  to  19'f,  from  cone 
010  toward  cone  02,  giA'ing  a  fair  range  of  pinks  and  buffs.  Fusion 
begins  slightly  above  cone  02,  Avithout  preliminary  vitrification  or  the 
develo]iment  of  steel  hardness.  The  fired  porosity  is  too  high  to  permit 
the  manufacture  of  structural  Avare  of  good  quality.  The  total 
maximum  linear  shrinkage,  plastic  basis,  is  10.8%,  at  cone  02.  The  best 
firing  range  is  betAveen  c(mes  04  and  02.  No  charts  of  linear  firing 
shrinkage  or  absorption  are  giA'en. 

Ko.41  {\^.'■l{)-l).  San  Diego  County.  Escondido.  II.  T.  :\lorris.  Thi^ 
is  a  poor  quality  of  conniion-brick  clay,  containing  too  much  lime  for 
satisfactory  use.  It  efferA^esces  strongly  in  liydrocliloric  acid.  The 
plasticity  is  sufficient  for  brick-])ressing,  tlic  dry  strengtli  is  medium, 
the  drying  characteristics  are  satisfactory,  and  in  the  dry  state  the 
clay  is  hard  and  coarse-grained.  The  colors  are :  dry,  19"f ;  Avet,  21''''f ; 
cones  010  to  06,  15";  cones  04  and  02,  1:}";  and  cone  1+,  9"i,  with 


CLAY  RESOURCES  AND  CERAMIC  INDUSTRY  340 

ycllow-tjrcon  blotches  inflieatin<r  tho  presence  of  lime.  The  fired  colors 
;ii-e  too  (lull  for  "rood  exterior  effects.  Fiiifrer-iifiil  iiMrdness  is  present 
in  the  dried  strife,  hut  steel  hairiness  is  not  devehtped  below  the  fusion 
point.  Fusion  coiiuneiices  at  cone  1-|-,  without  i)revi()us  vitrification. 
Tlie  iii;i.\inuini  total  linear  shrinkage  is  (i.d'/r,  at  cone  1+.  The  best 
firing  range  is  from  cone  010  to  cone  02. 

No.  46  (p.  195).  8an  Bernardino  County.  Government  Holes,  12  m. 
E.  of  Ciina.  R.  II.  Ilolliman.  This  is  a  residual  kaolin,  too  high  in 
coloring  compounds,  fluxes  and  non-plastics  to  be  of  value.  Tliere  is 
strong  effervescence  in  liydrochloric  acid.  As  the  deposit  has  been 
reported  on  numerous  occasions,  the  test  data  are  presented  for  those 
who  may  be  interested.  The  material  has  fair,  though  short,  plasticity, 
mi'dium  dry  strength,  and  is  hard  and  close-textured  in  the  dried  state. 
The  colors  are  :  dry,  yellowish  grav ;  wet,  17"'f ;  cone  010,  13"f ;  cones  08 
and  06,  13"d;  cones  04  and  02,^13"b;  cone  1,  13"";  cones  3  and  5, 
17"".  Finger-nail  hardness  is  developed  below  cone  010,  and  steel 
hardness  at  cone  3.  Bloating  begins  at  cone  5,  and  complete  loss  of 
shape  occurs  at  cone  13  (with  the  laboratory  firing  schedule  used).  The 
maximum  total  linear  shrinkage,  plastic  basis,  is  7.3%,  at  cone  5. 

No.  115  and  116  (p.  90).  San  Bernardino  County.  Near  Rosamond. 
Merry  Widow  ]\Iine.  These  are  samples  of  fault  gouge  and  altered 
volcanic  rock  from  an  abandoned  gold  mine.  Many  clays  of  this  type 
are  called  to  the  attention  of  the  State  ^Mining  Bureau.  The}'  are 
usually  worthless  from  the  ceramic  standpoint,  on  account  of  weak 
plasticity,  excessive  shrinkage,  poor  fired  colors,  low  fusion  point,  short 
vitrification  range,  and  low  fired  strength.  Test  data  are  presented 
for  two  varieties  for  the  purpose  of  pointing  out  the  defects  of  such 
material.  No.  llo  is  a  fault  gouge.  It  has  sticky  and  weak  plasticity, 
liigh  dry  strength,  and  in  the  dried  condition,  is  hard,  medium-grained 
and  medium-textured.  The  high  ratio  of  pore  water  to  shrinkage  water 
sliould  be  especially  noted.  The  colors  are:  dry,  nearly  white;  wet, 
grayish  white;  cone  010,  13"d;  cones  08  to  04,  15"b;  cones  02  to  3, 
15"i ;  cone  5,  15".  Finger-nail  hardness  is  present  in  the  dried  state, 
and  steel  hardness  appears  at  cone  04.  The  fired  structure  is  weak, 
and  wdien  fired  below  cone  02,  is  granular.  At  cone  02  and  above,  the 
structure  is  glassy.  Most  of  the  fired  test  pieces  have  one  or  more  large 
cracks.  Vitrification  is  complete  at  cone  1,  but  kiln-marking  begins  at 
this  point,  and  bloating  begins  at  cone  3.  The  total  linear  shrinkage, 
plastic  basis,  is  24.5%  at  cone  1. 

No.  116  is  a  sample  of  decomposed  trachyte  (?).  The  properties  are 
sinular  to  those  of  No.  115,  but  the  shrinkage  is  less,  and  the  fired 
structure  is  stronger. 

No.  205  (p.  229).  Stanislaus  County.  Near  Patterson.  Cummings 
Ranch.  This  is  a  shale  with  poor  plasticity  and  medium  dry  strength. 
In  the  dried  condition  it  is  medium  hard,  coarse-grained,  and  open- 
textured.  The  colors  are :  dry,  yellowish  white ;  wet,  17"d ;  cones  010 
to  06,  17"d;  cones  04  to  3,  17"b;  cone  7,  17"d.  Steel  hardness  is  not 
developed  up  to  the  firing  limit  studied,  cone  9.  The  fired  structure  is 
moderately  strong,  sound,  granular,  and  open.  The  surface  texture  is 
slightly  rough.  The  grains  composing  the  mass  are  heterogeneous  in 
color.     The  total  linear  shrinkage,  plastic  basis,  at  cone  9,  is  13.1%. 


350  DTVIRTOX  OF  MIXES  AXD  MIXING 

The  clay  would  need  to  be  mixed  with  more  plastic  material  in  order 
to  permit  its  successful  use  in  comnimi  l)rick  or  face  brick  manufacture. 

No.  :}6:2  (p.  159).  Placer  County.  East  of  Lincoln.  Valley  View 
]\Iine.  This  is  an  altered  irrneous  rock  of  undetermined  oritrin  and 
composition.  It  develops  <;oo(l  plasticity,  although  a  large  proportion 
of  the  material  is  non-plastic.  The  dry  strength  is  medium,  and  in  the 
dried  condition,  it  is  medium  hard,  open-textured,  and  heterogeneous. 
The  colors  are:  dry,  17"'f ;  wet,  17'"b;  cones  010  to  3,  15"d;  cone  7, 
17"'i.  The  fired  colors  are  too  dull  for  pleasing  brick  colors.  Steel 
hardness  is  developed  at  cone  7.  The  fired  structure  is  sound,  and 
medium  strong,  except  for  superficial  cracks  at  cone  7.  Fusion  Avitliout 
vitrification  begins  above  cone  7.  The  total  linear  shrinkage,  ])lastic 
basis,  at  cone  7,  is  10.7 /c.     The  material  has  doubtful  ceramic  value. 

TABLE    No.  28. 

IV.  Clays   Burning    Dirty    White,   Cream    White,   or   Yellowish    White. 

17.  Generally  contain   calcium   or   magnesium   carbonate   or   both,   and    seldom   reach 


low 

porosity.     Very 

short  fi 

ring 

range. 

Soften- 

Clay 

ing  pt. 

No. 

%  S.W. 

%  P.W. 

%  W.P. 

D.T.S. 

% 

D.V.S. 

</c  D.L.S. 

in  cones 

3 

13.6 

26.3 

39.9 

463 

20.8 

6.1 

41 

11.2 

18.5 

29.7 

322 

19.6 

6.2 

4G 

7.6 

10.2 

17.8 

579 

15.7 

5.1 

115 

16.5 

37.6 

54.1 

432 

20.4 

6.4 

116 

24.9 

29.1 

54.0 

550 

34.4 

10.4 

163 

43.0 

24.1 

67.1 

-1-35  0 

66.8 

18.4 

205 

9.4 

39.8 

49.2 

269 

11.4 

3.6 

262 

10.1 

18.2                   28.3 
cent  shrinkage   water. 

334 

18.0 

5.7 

% 

S.V^.       =  Per 

% 

P.W.      =  Per 

cent  poi 

•e  water. 

% 

W.P.      =  Per 

cent  water  of  plasticity 

D.T.S.         =  Dry 

transvei 

rse  strength,  pounds  per 

square  inch, 

without  sand 

% 

D.V.S.   =  Dry 

ins:  shrinkage,   per  cent 

dry   voh 

imie. 

% 

D.L.S.    =  Calculated  li 

near  drying  shr 

inkage, 

per  cent  dry 

length. 

CLAY  RESOURCES  AND  CERAMIC   INDUSTRY 


351 


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352 


DIVISION  OF  MINES  AND  MINING 


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cJjAY  resources  and  ceramic  industry  353 

chemical  analyses. 

Table  No.  ;!()  <;ivcs  cliomieal  analyses  of  ('crtaiii  clays  from  (li'i)osits 
that  were  sampled  and  tested.  About  one-half  of  the  analyses  were 
made  on  a  portion  of  the  same  samples  that  were  tested  for  ceramic 
l)roperties  and  therefore  can  be  directly  correlated  with  the  results  of 
the  tests.  Tlie  other  lialf  of  llu'  analyses  were  compiled  from  the  litera- 
ture and  from  data  presented  by  certain  of  the  clay  manufacturers. 
The  sami)le  nund)ers  to  which  these  analyses  correspond  are  given  in 
parentheses,  but  owino;  to  variations  in  the  character  of  the  clay  being 
mined  at  ditl'ercnt  times,  the  anal^'ses  of  the  samples  actually  tested 
may  be  considerably  different  from  those  given  in  the  table. 

Table  No.  31  presents  a  group  of  chemical  analj'ses  of  deposits  that 
were  not  sampled.  Very  few  of  these  clays  have  possible  uses  in  ceramic 
manufacture,  except  for  common  brick.  The  analyses  are  given  as 
being  of  possible  interest  in  the  future  and  to  serve  as  a  guide  to  the 
character  of  material  to  be  found  in  the  localities  noted. 


2:^ — .-,^07!> 


354 


DIVISION  OF  MINES  AND  MINING 


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Amer.  Ref.  Co., 

11:  A.C 
II:  A.  C. 
11:  A.  C. 

t.  Stand 
t.  Coors 
t.  Coors 
11  (G.  M. 

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hill:  El 
hill:G. 
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a. 

1     ^^j_:^c^ 

11,  A. 
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CO  CO 

CI  -^    1  [   CD  CM    j 

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lor^ 

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CO  CO 

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DIVISION  OF  MINES  AND  MINING 


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111 

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Q. 

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o 
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s 

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o  o 


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c  =:  a  c  c  c:  c 


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;  :^  *^  ^  ui  iii  lii  ui  tii  ui  t:d  tij  ui  ui  t4 


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CLAY  RESOURCES  AND  CERAMIC  INDUSTRY 


357 


INDEX  OF  CLAY  SAMPLE  NUMBERS 

^§1 

4 

CO  r* 

?g- 

?«-! 

m 

■  to 

1  ^ 

■a  at 

•a  a. 

253 

13 

•Si 

»g- 

:  f^- 

;  F 

;  '5.'"^ 

:  f 

•  5^ 

;  F 

;  H.'"^ 

;  S 

;  v-^ 

;  -^ 

\  f 

1  5" 

,  _3 

* 

i  1 

1  f 

i  f 

1 

218 

338 

59 

265 

111 

176 

315 

162 

159 

223 

141 

343 

2 

218 

338 

60 

"  ioo" 

340 

112 

178 

324 

163 

159 

"m 

229 

175 

300 

3 

218 

348 

61 

102 

341 

113 

178 

324 

164 

150 

230 

175 

300 

4 

234 

338 

62 

145 

259 

114 

90 

312 

165 

159 

231 

175 

281 

5 

234 

339 

63 

140 

260 

115 

90 

349 

166 

138 

"316" 

232 

175 

281 

6 

234 

339 

64 

140 

260 

116 

90 

349 

167 

138 

315 

233 

70 

7 

169 

328 

65 

141 

322 

117 

131 

324 

168 

136 

313 

234 

70 

8 

169 

3^1 

66 

179 

277 

118 

192 

341 

169 

138 

313 

235 

70 

"""263 

9 

169 

287 

67 

179 

277 

119 

74 

325 

170 

136 

315 

236 

68 

263 

10 

169 

334 

69 

169 

323 

120 

53 

272 

171 

136 

329 

237 

68 

263 

11 

169 

257 

70 

169 

272 

121 

53 

302 

172 

136 

342 

238 

70 

316 

12 

169 

257 

71 

169 

278 

122 

53 

328 

173 

235 

313 

239 

52 

281 

13 

169 

296 

72 

169 

328 

123 

56 

335 

175 

65 

304 

240 

52 

274 

14 

169 

287 

73 

169 

323 

124 

56 

302 

176 

66 

325 

243 

52 

15 

169 

264 

74 

175 

278 

125 

53 

273 

177 

66 

336 

244 

52 

"281 

16 

169 

314 

75 

175 

335 

126 

52 

279 

178 

65 

325 

245 

52 

300 

17 

169 

277 

76 

175 

288 ; 

127 

57 

335 

180 

77 

326 

246 

52 

300 

18 

169 

321 

77 

175 

278 

128 

54 

261 

181 

80 

336 

247 

52 

300 

19 

169 

311 

78 

175 

288 

129 

62 

261 

182 

81 

326 

248 

52 

301 

21 

169 

334 

79 

175 

278 

130 

62 

290 

183 

81 

326 

249 

52 

301 

22 

169 

335 

80 

175 

297 

131 

62 

329 

184 

80 

342 

250 

52 

282 

23 

169 

277 

81 

175 

289 

133 

63 

298 

185 

80 

342 

251 

52 

327 

24 

169 

321 

82 

175 

315 

134 

58 

261 

188 

92 

336 

252 

52 

305 

25 

169 

311 

83 

175 

297 

135 

58 

312 

190 

133 

261 

253 

52 

301 

26 

169 

321 

84 

175 

289 

136 

58 

302 

191 

133 

280 

254 

52 

301 

27 

169 

287 

85 

175 

298 

137 

57 

266 

192 

133 

281 

255 

52 

313 

28 

169 

264 

86 

175 

279 

138 

57 

280 

194 

227 

262 

256 

52 

330 

29 

169 

264 

87 

175 

279 

139 

57 

290 

195 

227 

262 

257 

52 

291 

30 

203 

339 

88 

315 

140 

56 

280 

197 

227 

291 

258 

52 

292 

31 

204 

340 

89 

341 

141 

58 

280 

198 

125 

329 

259 

45 

263 

32 

205 

322 

90 

"173" 

265 

142 

58 

280 

199 

74 

326 

261 

159 

328 

33 

205 

287 

91 

173 

260 

143 

185 

274 

200 

73 

342 

262 

159 

350 

34 

205 

288 

92 

173 

289 

144 

185 

273 

201 

69 

305 

263 

159 

292 

35 

202 

322 

93 

173 

265 

145 

156 

291 

202 

68 

337 

264 

42 

343 

36 

201 

311 

94 

173 

311 

146 

156 

303 

203 

68 

337 

265 

40 

343 

37 

201 

259 

95 

173 

311 

147 

156 

303 

204 

68 

299 

266 

140 

292 

38 

201 

259 

96 

173 

272 

148 

156 

336 

205 

229 

349 

268 

140 

260 

39 

203 

296 

97 

173 

290 

149 

156 

298 

206 

232 

327 

269 

316 

40 

203 

322 

98 

173 

272 

150 

156 

291 

208 

57 

262 

270 

"140" 

282 

41 

202 

348 

99 

173 

312 

151 

156 

303 

209 

59 

263 

271 

169 

301 

42 

181 

340 

100 

173 

323 

152 

147 

304 

210 

186 

337 

272 

169 

292 

43 

181 

340 

101 

173 

298 

153 

147 

299 

211 

81 

342 

273 

169 

273 

44 

196 

264 

102 

173 

290 

155 

151 

325 

212 

186 

337 

274 

169 

302 

45 

196 

264 

103 

173 

260 

156 

151 

299 

213 

59 

299 

280 

147 

305 

46 

195 

349 

104 

173 

279 

157 

151 

304 

214 

131 

327 

282 

141 

282 

53 

195 

288 

105 

173 

324 

158 

138 

216 

213 

327 

283a 

232 

314 

55 

195 

314 

108 

176 

290 

159 

137 

"261 

217 

213 

327 

283b 

232 

314 

56 

297 

109 

176 

266 

160 

137 

261 

218 

181 

329 

284 

232 

316 

57 

"194" 

264 

110 

176 

298 

161 

159 

221 

141 

330 

285 

232 

282 

358 


DIVISION    OF    IMINES   AND   MINING 
INDEX  TO  CLAY  SAMPLES,  BY  COUNTIES 


County 

Name  of  property 

Designation  of  clay 

CO 
» 

B 
•a. 

p 

03 

p 

Description  of 
property, 
page 

-9 

W.  S.  Dickey  CM.  Co 

M  &  S  Tile  Co. 

Niles __ 

265 
264 
259 

15 
15 

1 

40 
42 
45 

343 

Niles 

Tesla 

343 

263 

Arroyo  Seco  Grant 

• 

Baker 

126 
125 
120 
122 
121 
240 
245 
247 
246 
248 
249 
250 
251 
252 
253 
254 
255 
239 
256 
258 
257 
244 
243 
128 
124 
123 

5 

4 
3 

13 
8 
4 
7 
7 
7 
7 
7 
5 

12 
8 
7 
7 
9 
5 

13 
6 
6 
5 

8 
14 

52 
53 
53 
53 
53 
52 
52 
52 
52 
52 
52 
52 
52 
52 
52 
52 
52 
52 
52 
52 
52 
52 
52 
54 
56 
56 

279 

Gage 

273 

Jones  Butte  fireclay 

Jones  Butte  laterite 

272 
328 

.Tones  Butte  'unctuous'.. 

Lot  237  E.  side            

302 
274 

Hole  55-1 

300 

55-2 

300 

55-3... 

300 

56-1 

.301 

56-2 

.301 

56-3 

282 

57-1 

327 

57-2 

57-3            .  . 

305 
301 

57-4... -. 

.301 

57-5_ 

Lot  254,  N.  E.  cor 

313 
281 

Lot  255,  Hole  60 

61 

330 
291 

62 

Lot  324.  Hole  54 

Lot  336,  Hole  47 

292 
281 

Shepard  sand 

261 

Yaru  No.  1... 

Yarn  No.  2 

302 
335 

Bacon  and  Bacon 

Bacon  blue.. 

139 
138 
127 
137 

6 

5 

14 

2 

57 
57 
57 
57 

290 

Bacon  bottom           ..  _ 

280 

Bacon  red 

335 

Chocolate 

266 

Carlile 

N.  Clark  &  Sons 

Carlile  sand 

208 
134 
136 
135 
213 
209 
141 
142 
140 
130 
131 
129 
133 

1 
1 
8 
9 
7 
1 
5 
5 
5 
6 
13 
62 
7 

57 
58 
58 
58 
59 
59 
58 
58 
60 
61 
61 
61 
63 

262 

Clark  sand       . 

261 

Eckland 

Fancher  (W.  S.  Dickey  C.  M.  Co.) 

lone  Fire  Brick  Co 

Newman  Estate 

Yosemite  Portland  Cement  Co.. 

Dosch 

Doschstripping          

302 
312 

Mottled 

299 

Sand 

263 

Fancher  yellow 

280 

Fancher  )lue 

280 

Sand 

280 

Carbonaceous  sand  ..   

290 

Pink  mottled 

329 

Sand .- 

Harvey 

261 
298 

Butte 

Lund  Ranch 

Common. 

Common 

178-1 
-2 
-3 

177 
176 
175 

12 
12 
12 
14 

12 

8 

65 
65 
65 
66 
66 
66 

325 

Oroville-Quincy  Road.- 

Table  Mt.  C.  P.  Co. 

325 
325 
336 

Decomp.  igneous. 

Yellow  plastic...  .  .     .-  .  . 

325 
304 

Calaveras 

California  Pottery  Co. 

Nigger  Hillkaolin' 

Nigger  Hill'kaolin' 

Valley  Spgs.  blue 

Valley  Spgs.  pink-mottled 

Valley  Spgs.  yellow 

Helisma.-   

236 
237 
204 
202 
203 
201 
238 
233 
234 
235 

1 

1 

7 

14 

14 

8 

10 

68 
68 
68 
68 
68 
69 
70 
70 
70 
70 

263 

Helisma 

Penn.  Min.  Co 

Texas  Min.  Co.. 

263 
299 
337 
337 
305 

Kaolinized  schist 

316 

Kaolinized  schist..  

Kaolinized  schist..     

Kaolinized  schist. 

263 

Contra  Costa 

N.  Clark  &  Sons 

Walnut  Cr.  shale 

Shale                          .  . 

200 
199 
119 

15 
12 
12 

73 
73 
74 

342 

Port  Costa  Brick  Co. 

326 

RichmonH  P.  R.  Cn 

Shale 

325 

Del  Norte     ..     . 

Musick 

Common 

180 

12 

77 

326 

Humboldt 

Angpl  R.anp,h 

Pottery  (red)... 

Common 

Common 

Common _ 

Common 

181 
185 
211 
183 
182 

14 
15 
15 
12 
12 

80 
80 
81 
81 
81 

336 

Loof  bourrow 

Strong's  Station 

Sunny  .Avenue 

Thompson  Brick  Co 

342 
342 
326 
326 

fl.AV   KKSOrRCES   AND  CERAMIC   INDISTRY 
INDEX  TO  CLAY  SAMPLES.  BY  COUNTIES-^Contlnued 


351) 


County 

Name  of  property 

Designation  of  clay 

i 
p 

Description  of 
property, 
page 

Class  No 

H 

;   5 

Amer.  Silica  Co 

Death  Valley  superfine 

269 

10 

316 

Merrv  Widow  Mine 

Impure  kaolin 

115 
116 
114 

17 

17 

9 

90 
90 
89 

349 

Titus     .                           .  

Impure  kaolin..  . 

349 

Titus 

312 

Lake 

Keiseyville     _   .               .      . 

Common 

188 

14 

92 

336 

I.nR  \nceles 

Da\i(ison  Brick  Co. 

Common 

60 
61 

15 
15 

100 
102 

340 

Gladding.  McBean  &  Co 

Santa  Monica  common 

341 

Msrin 

McNear  Brick  Co. 

Shale _... 

198 

13 

124 

329 

Area.                           

Common 

117 
214 

12 
12 

130 
131 

324 

Monterey  Mission  Tile  Co 

Adobe 

327 

Clark  and  Marsh 

Kaolin,  average- 

190 
191 
192 

1 
5 
5 

133 
133 
133 

261 

Kaolin,  selected                 

280 

Kaolin,  lower  tuimel 

281 

Nevada 

Banner  Mt.  Road 

170 
168 
172 
171 
159 
160 
166 
167 
169 
158 

10 

9 

15 

13 

1 

.1 

10 
9 

136 
136 
136 
136 
137 
137 
138 
138 
138 
138 

315 

Beascr  Ranch 

313 

Pipe  clay 

342 

North  Bloomfield  Rd 

329 

Pine  Hill  Mine 

Kiinlin 

261 

Sonntaff  Ranch 

Kaolin                       .  

261 

Kaolin.. 

316 

Kaolin 

315 

313 

Sweet  Ranch  (Pine  Hill) 

Kaolin          

Amreco  fireclay 

266 

270 

268 

64 

63 

65 

221 

282 

223 

62 

6 
5 

1 
1 
1 

12 

12 

5 

15 

1 

140 
140 
140 
140 
140 
140 
141 
141 
142 
145 

292 

Brea  C.  P.  Co. 

.\rc  fireclay 

282 

1^1  Toro  crude    .                

260 

Hunter  Ranch — lower 

Hunter  Ranch— upper 

Common 

260 
260 
322 

Gladding,  McBean  &  Co 

Vitrefrax  Co. 

Goat  Ranch  flint 

330 

Goat  Ranch  flint                  

282 

Goat  Ranch  shale  M  M  3 

O'Neill  Ranch  fireclay 

343 
259 

Placer 

Clay  Corporation  of  Cal 

Gladding,  McBean  &  Co 

Lincoln  C.  P.  Co. 

Lincoln  fireclay 

280 
152 
153 
156 
155 
157 
145 
146 
147 
148 
149 
150 
151 
165 
162 
163 
164 
161 
261 
262 
263 

8 
8 
7 
7 

12 
8 
6 
8 
8 

14 
7 
6 
8 

■"17" 

""\2 

17 

6 

147 
147 
147 
152 
152 
152 
156 
156 
156 
156 
156 
156 
156 
159 
159 
159 
159 
159 
159 
159 
159 

305 

Lincoln  top  clay 

304 

299 

Lincoln  fire-proofing         

299 

325 

Lincoln  terra  cotta 

304 

No.O .- 

291 

M  iacellancous 

No.  1-6 

303 

No.  7 

303 

No  8 

336 

No.9 

298 

No  10                           

291 

Washed  china  clay 

303 

Alta 

Baxter                

Baxter         .  

350 

Baxter                     

Kaolin  (impure) 

328 

350 

Kaolin  (imoure)        ,        

292 

Pivprfltdp 

Alberhill  C  &  C  Co 

A-clay          .  

14 

17 

18 

11 

12 

19 

9 

271 

272 

274 

10 

29 

13 

15 

27 

6 

5 

12 

1 

1 
9 
6 
7 
6 
7 
14 
2 
7 
2 
6 

169 
169 
169 
169 
169 
169 
169 
169 
169 
169 
169 
169 
169 
169 
169 

287 

Bone  W-105 

277 

Clark  tunnel  mottled 

China  E-101             

321 

257 

China  E-102 

257 

Diamond                           

311 

Hillblue                  

287 

Hill  blue,  lower  tunnel 

Hill  blue,  main  tunnel 

Hill  blue,  upper  tunnel 

301 
292 
302 
3.34 

264 

Main  tunnel  ex.  select 

Ma.in  tunnel  select 

296 
264 

No.  10 

287 

360 


DIVISION    OF    MINES    AND    MINING 
INDEX  TO  CLAY  SAMPLES.  BY  COUNTIES— Continued 


County 

Name  of  property 

Designation  of  clay 

CD 

B 

•3, 

p 

o 

»" 

CO 

p 

Description  of 
property, 
page 

:  ? 

Pink  mottled.... 

7 
8 
21 
28 
273 
23 
16 
25 
24 
26 
22 

13 

12 

14 

2 

3 

5 

10 
9 
12 
12 
14 

169 
169 
169 
169 
169 
169 
169 
169 
169 
169 
169 

328 

Red  No.  2 

321 

Sagger. 

334 

SH-3.. . 

264 

SH-4 

273 

West  blue 

277 

West  blue  select 

314 

West  tunnel  blue 

311 

West  tunnel  mottled. 

321 

Westyellow.. . 

321 

Yellow  Owl  Cut... 

335 

Emsco  Clay  Co.  (Harrington  pit) 

Bone.  -.  

73 
71 
72 
69 
70 

12 

5 

13 

12 

3 

171 
171 
171 
171 
171 

323 

Pink  mottled 

278 

Red. 

328 

Red  Horse... . 

323 

White  (No.  5) 

272 

Gladding,  McBean  &  Co.  (Alber- 
hillpitB) 

Bone  (W-105?) 

98 

90 

93 

91 

92 

96 

103 

104 

105 

102 

101 

97 

99 

94 

95 

100 

3 

2 

2 
1 
6 
3 
1 
5 

12 
6 
7 
6 
9 
9 
9 

12 

173 
173 
173 
173 
173 
173 
173 
173 
173 
173 
173 
173 
173 
173 
173 
173 

272 

Main  tunnel.. 

265 

Main  tunnelselect 

265 

Main  tunnel  sand 

260 

Main  tunnel  yellow..  .  . 

289 

No.  10 

272 

Sloan,  bone . 

260 

Sloan,  No.  5 

279 

Sloan,  red.. . 

324 

Sloan,  sand . 

290 

Sloan,  white 

298 

Smooth  bunker 

290 

Tile.... 

312 

West  blue 

311 

West  blueselect 

311 

Yellow  stripping 

323 

Hudson  Ranch- 

Clay.     .. 

89 
88 

15 
10 

341 

Sand 

315 

Los  Angeles  Brick  Co 

Bone,  high-alumina 

231 
87 

232 
82 

229 

230 
78 
77 
76 
81 
86 
85 
84 
83 
75 
74 
79 
80 

5 
5 
5 
10 
7 
7 
6 
5 

t 
5 

7 
6 
7 
14 
5 
5 
7 

175 
175 
175 
175 
175 
175 
175 
175 
175 
175 
175 
175 
175 
175 
175 
175 
175 
175 

281 

Bone,  smooth 

Bone. smooth . 

279 
281 

Clay  shale . 

315 

No.  7 

300 

No.9 

300 

No.  10 

288 

No.  20 

278 

.No.  23 

288 

No.  25 

289 

No.  26  bone 

279 

Pink  mottled 

298 

P.  M.  fireclay 

289 

Red 

297 

Red  No.  2 

335 

West  bone 

278 

West  pit  fireclay 

278 

West  pit  mottled ... 

297 

Pacific  C.  P.  Co.  (Alberhill  and 
Corona  pits) 

Douglas . 

110 
111 
109 
108 
112 
113 
67 
66 

7 

10 
2 
6 
12 
12 
5 
5 

176 
176 
176 
176 
178 
178 
179 
179 

298 

Douglas  lower 

315 

Douglas  main  tunnel 

Douglas  upper. .  

266 
290 

Hoist  pit  blue  ... 

324 

Hoist  pit  red. 

324 

McKnight  fireclay. 

277 

McKnight  sewer  pipe 

277 

Temeseal  Water  Co 

Pink  mottled    .  . 

218 
42 
43 

13 
15 
15 

181 
181 
181 

329 

Wilson,  J.  W 

Common..  .  . 

340 

Common 

340 

Sacramento 

Michigan  Bar. . 

Cutter 

143 
144 

210 
212 

4 

3 

14 

14 

185 
185 
186 
186 

274 

Natoma  Clay  Co 

Van  Vleck.. 

273 

No.  1       . 

337 

No.3 

337 

CLAV  RHSOIHCES   AM)   CERAMIC   IXIHSTHV 
INDEX  TO  CLAY  SAMPLES.  BY  COUNTIES— Continued 


861 


County 

Name  of  property 

Designation  of  clay 

■2. 
p 

Q 

p 

Description  of 
property, 
page 

;  f 

Paicincs 

Common 

118 

15 

192 

341 

Hart  kaolin 

57 
55 
46 
53 
44 
45 

2 

10 

17 

6 

2 

2 

194 
195 
195 
196 
196 
196 

264 

Gladding,  McBean  &  Co 

Bryman  clay _         .. 

314 

Impure  kaolin 

349 

Millet  &  Kennedy     ..  

Buff-burning 

Pacific  kaolin  (Hart) 

288 

Standard  San.  Mfg.  Co. 

264 

Pacific  kaolin  (Hart) 

264 

San  Dieffo 

California  C.  P.  Co 

Cardiff  fireclay 

36 
38 
37 
35 
41 
39 
40 
30 
31 
33 
34 
32 

9 

1 

1 

12 

17 

7 

12 

15 

15 

6 

6 

12 

201 
201 
201 
202 
202 
203 
203 
203 
204 
205 
205 
205 

311 

ElCajonMt 

Kaolin,  ayeragc 

259 

Gladding.  McBean  &  Co 

Morris.H.  T 

Kaolin, selected..  . 

259 

Cardiff 

322 

Common 

348 

Pacific  C.  P.  Co. 

Kelley  Ranch  white 

296 

San  Diego  T.  &  B.  Co... 

Kelley  Ranch  yellow 

322 

Rose  Canyon .. 

339 

Rose  Canyon 

340 

Vitrified  Products  Co. 

Cardiff  fireclay 

287 

Cardiff  fireclay.     

287 

Linda  Vista  shale 

322 

San  Luis  Obispo 

Santa  Margarita 

Shale 

216 
217 

12 
12 

215 
215 

327 

Shale 

327 

S:\nt.a  Barbara 

Brentner                                

Carpinteria 

3 
1 

2 

17 
15 
15 

218 
218 
218 

.348 

Muegenberg&  Whitiker. .- 

Santa  Barbara 

338 

Toro  Canyon .     

338 

Beltane.-       .          

Buff -burning 

197 
194 
195 

6 

1 
1 

227 
228 
228 

291 

Weiss  J.  H. 

Average  white . 

262 

Selected  white.. ,. 

262 

Cummings  Ranch 

Shale 

205 

17 

229 

349 

Tulare 

Sears  W.  A.  - 

Kaolin  (impure) 

Kaolin  (impure) 

283-A 
283-B 
284 
285 

9 
9 

10 
5 

232 

232 

232 

.   232 

314 

314 

Kaolin  (impure)                 

316 

Kaolin  (impure) 

282 

Valencia  Heights 

Shale                      .      

206 

12 

232 

327 

Anderson  &  Hardison 

(Santa  Paula) 

Blue        

6 
5 

4 

15 
15 
15 

234 
234 
234 

339 

Peonle's  Lumber  Co. 

339 

Yellow 

338 

Yuba 

Demnsey  Ranch 

Kaolin  (impure) 

173 

9 

235 

313 

Florida                      

Edgar  koalin 

59 
59 

2 

7 

265 

Germany 

Fireclay                       .   ..   .. 

297 

GEiNERAL  INDEX. 

A 

Page 

Abbe    Ranch    192 

Al)rasives,  clay  suitable  for_- ._^ , ^^ 253,  254 

Absorption . ^» ^^. ^^ . 245 

Acme    Brick    Comi>any    ^_^ ^_. . 94 

Alameda,   plants   in   40 

Alanifda    County    38 

clay    resources 38 

bibliography    49 

Albany   (see  Berkeley). 

Albany  slip,  use  of . 49 

Alberhill 162-163,  175-17G,  178,180 

clay,  use  of 93-98,  100,  101,  104,  107,  109,  117,  118,  119,  123,  215,  216 

Alberhill  Coal  and  Clay  Company 162 

clav  deposits 169 

clay  tests 257,  264,  273,  277,  287,  292,  296,  301,  302,  311,  314,  321,  328,  334,  335 

Alberhill-Corona  district,   description   of 162 

Alhambra 94 

Alhambra  Kilns,   Inc.   94 

Aliso  Creek 139 

Alpine   Quicksilver  Mining  Company 192 

Alta,  clay  near 159 

Alumina,  high,  clay   (see  bone  clay). 

Aluminum  oxide 121 

Amador   County   49 

clay  resources 50 

bibliography 63 

Amador  Kaolin  Company 63 

Amargosa  River 88 

Amboy,  bentonite  at 97 

American  Ceramic   Society   238,  244,  252 

American  China   Comjiany    94 

American  Encaustic   Tiling   Company,    Ltd.    95 

American   Portland   Cement    Company    85 

American   Pottery  Company 201 

American   Refractories  Company 96 

Amreco  fire  clay,  tests  of 292 

Arc  fire  clay,  tests  of 282 

American  Silica  Company 140 

Death  Valley  clay,  tests  of 316 

Hunter  Ranch   clay 140 

Robinson   Ranch   clay 140 

Amick,  "W.  D.,  property    (lone) 63 

'Amreco'  fire  clay,  tests  of 292 

Anaheim 144 

Analyses,  chemical,  tables  of 353-356 

value   of 252 

Andalusite    19 

Ander.son 223 

Anderson,  Andres 187 

Anderson,  Mrs.  A.  E.  L. 107 

Anderson,   H.   P. 92 

Anderson  Ranch 92 

Anderson  and  Hardison 234 

clay,   tests  of 339 

Angel   Ranch   clav 80 

tests  of  ^ 336 

use   of 39 

Angels  Camn 68 

Angulo,  R.  F..  and  Sons 97,  218 

Angulo  Tile  Company 

Plant  No.   1   218 

Plant  No.   2 97 

Antioch 75 

Area,  Joe 130 

clay,  tests  of 324 

Area  roofing  tile  plant 130 

Areata 79-  80 

Architectural   design 29 

Armstrong,  H.  C. 105 

Arnold,  Ralph   222 

Arrovo   Seco   Grant 51 

clav,  tests  of 261,  272, 

273,  274,  279,  281,  282,  291,  292,  300,  301,  302,  305,  313,  327,  328,  330,335 

core   drill   samnles   52 

Art  pottery,  manufacture  of,  in  California 30 

Art  ware 38,   39,  45 

Ashbury,  F.   A. 227 

Atlas  Fire  Brick  Company 97 

ganister 194 

Austin,  L.  ^:V. 221 

Axelson,   Victor    ^^__.,„,^.,_,^,_^__J 187 


INDEX  363 

B 

Page 

Hachman,  W.  E. 98 

Bacon,   M.  J.   41,  56 

Bacon   and   Bacon   51,  5(i 

clays,  tests  of 266,  280,  290,  298,  3:i5 

Bacon  Red  pit   (lone) 57 

Baden  Brick  Company 215 

Baker,   A.  A. 220 

Baker,   Joseph 40 

Baker,  Levi   S.    40 

Baker  Clay,  tests  of 279 

Bakersfield 89 

Bakersfield  Rock  and  Gravel  Company 89 

Bakersfield  Sandstone  Brick  Compan>' 89 

Ball,  Chas. 40 

Ball  clay,  definition  of 15 

resources  of,   in  California 19 

Bane,  T.  H. i:il 

Banner  Mountain   Road   clay 136 

tests  of 315 

Barber  pit    (see  Shepard  pit). 

Bardin,  Martha  E. 132 

Barstow     19 

Batchelder,  E.  A. 97 

Batchelder  Tile  Comiiany    (see  Batchelder-Wilson  Company). 

Batchelder-Wilson  Company 97 

similar  product 42 

Bauer,  J.  A.,  Pottery  Company 9S 

Baum,  J.  W. 252-25:! 

Bauxite   20 

Baxter,  clay  near 159 

Beaser,  P.  M. 136 

Beaser  Ranch  clay 136 

tests  of 313 

Beckman-Linden  Engineering  Corporation 42 

Belgian  sand 20,     28 

economic  factors 51 

Bellota    207 

Beltane 227 

clay  near 227 

tests  of 291 

Ben  All 183 

Benicia     i 225 

Bentley,   Arthur   78 

Bentonite,    Amboy    97 

Berg,  C.  B. 73 

Berkeley,   plants   in 38-40,    42,    45,     49 

Bethany    207 

Bettencourt,   J.   M.   41 

Betteravia    217 

Biddle,   C.   J.    121,  162 

Biggs     66 

Birtolini,    G.    208 

Bishop   Canyon    104 

Bisque  doll  heads 38 

Bitterwater    192 

Blake,  W.   P. 84 

Bleininger,   A.  V.   240 

Boggs,   G.   Ray    96,140 

Bohannon  Ranch   66 

Bolflng,     Chas. 220 

Bnlinas    Bay    124 

Bone  clay 20,     29 

Bonding  strength 241 

Bonistell,  C.  E. 234 

Bonner,   J.   M.   123 

Borego   Mountain    83,     84 

Boving,    P.   C.    103 

Bovvers.    Stejihen    140 

Bovles  Heights  Terrace  formation 107 

Bradbury.  E.  R. 142 

Bradlev,   W.   "SV.    13 

Bragdon,  W.  B. 39 

Branner,  J.  C. 222 

Brawley    83 

Brea    140 

Brea  Clay  Products  Company 140 

dav,  tests  of 322 

Brentner,    L,.    L,.    'IS 

clav  deposit 218 

tests    of    348 

Brick,  common,  clays  stiitable  for 255,  256 

Brick,   statistics    31 

Brick  handling  machines 26 


364  INDEX 

Page 

Bridge  House : 185 

Briggs,  C.  W. 13 

Briggs,  U.  N.    126 

Brooks,    Max    66 

Broughton,   H.   W.    99 

Brown,  II.  M.  and  R.  W. 121 

Brown,    J.    S.    84 

Brown,   Wm.    60 

Bruns,   L.   H.   221 

Bryman     195 

clay,  tests  of 314 

Buchler,    A.    E.    92 

Buena   Vista    50 

clay  deposit  near 58 

Buff-burning  clays,   tests   of 277-320 

Builders'  Supply  Company 218 

Bundock,  C.  E. 185 

Burchfiel,   B.  M.   13 

Burning   (see  firing). 

Burress,  Mrs.   I.   M.   41 

Burson    (see  Helisma). 

Butte   County   64 

clay    resources    64 

undeveloped    deposits    66 

Butte  County  Farms 67 

C 

Calaveras   County    67 

clay  resources 68 

geology    68 

Calaveras  formation 50,  68,    70 

California  Art  Tile  Company 72 

California  Bisque  Doll  Company 38 

California  Brick    Company    40 

California  Brick  and  Tile  Company 98 

California  China   Company 38 

California  Clay  Manufacturing  Company   (see  Los  Angeles  Brick  Company). 

California  Clay  Products  Company 99 

Cardiff  clay 201 

tests  of 311 

tile,  use  of 95 

California  Faience   Company   39 

'California    Mullite"    122 

California  Pottery  Company 39 

Merced  plant 128 

Nigger  Hill  deposit 68 

Oakland  plant 39 

Valley  Springs  clay  pit 68 

clays,  tests  of 299,  337 

California  Pressed  Brick  Company 40 

California  State  Life  Building 185 

Calistoga 132,  133 

Campo 19,  201 

Campo  Seco 68,    70 

clay,  tests  of 316 

Cannon,  D.  A. 183 

Cannon  and   Company   183 

Capay  235 

Carbofrax,  use  of,  in  test  kilns 243 

Carbondale    (see  lone). 

Carboniferous 50,   68,   70,   84,  200 

Cardiff 200,   201,  205 

clays,  tests  of 287,  288,  311,  322 

use   of 99 

Cardiff-Carlsbad  district 19 

Cargo  Muchacho  Mountains 83,  84,    87 

Carlile,  Mrs.  Sarah  E. 57 

Carlile  clay  and  sand  pit  (lone) 57 

Carlsbad 200,  203 

(see  also  under  Cardiff). 

Carmel 131 

Carmel  River 129 

Carmichael,  W.  J. 144 

Carnegie 207 

clays,   extinct   operations 45 

'Carnegie'   brick   209 

Carnegie  Brick  and  Pottery  Company 45,  208 

Carpinteria    218 

clay,  tests  of 348 

Carquinez  Brick  and  Tile  Company 76 

Carrizo  Mountain     83,     84 

Carson   Hill    68 

Casting  (of  clay  ware) 16 

Castroville    130 


INDEX  :](]') 

Page 

Cazadero    226 

Celito   Products   Company    30 

Cement,  use  of  lone  sand  in 51 

CfHienl  induslry 31 

Chemical   analyses,   tables  of 353-35U 

value    of    252 

Chemical   ware   21 

Cherokee 04 

Chicago  Park 136 

Chico 200 

Chico  formation 18,  64,  126,  139,  141,215 

China  clay,  definition  of 15 

resourc'i's  of,  in  California 19 

Chocolate  Mountains 84,    85 

Chocolate  pit    (lone)   57 

clay,  tests  of 266 

Chown,  J.  V. 236 

Chroma 249 

Chrome  brick 21 

Chualar 132 

cMma    195 

City  Brick  Company 100 

Clark,  A.  V. 40 

Clark,   G.    D.    4(i 

Clark,  J.  R. 133 

Clark  and  Marsh  kaolin 133 

tests  of 261,  280,  281 

use    of   38 

Clark,  N.,  and  Sons 40 

Alameda    pottery    , 40 

lone   properties   58 

Clark  sand,  tests  of 261 

clays,  tests  of 302 

clay  washing  plant 50 

Walnut  Creek  shale 73 

tests    of    342 

Clay,  classification  of 253 

by  color 251 

by  modulus  of  rupture 241 

by  ratio  of  pore  to  shrinkage  water 240 

by   refractoriness    248 

definition  of 15 

field   tests  of 237 

high  grade,  California,  geological  age  of 18 

laboratory  tests  of 238 

preparation    of    15 

products,    statistics    35 

samples,  list  of  tests  on 258 

tests,  buff-burning 277-320 

dirty  white-burning 348-352 

red-burning   321-352 

white-burning    237—276 

use  of,  in  oil  wells 234 

washing    (at   lone) 50,     57 

Clay  Corporation  of  California 147 

clays 151 

tests  of 299,  304,  305 

use   of   60 

Claycraft  Potteries,  Inc. 100 

Clay-Worker   121 

Clear    Lake    91 

Cleghorn,  P.  T. 209 

Clemson,    G.   W.    121 

Clinker  Brick  Company 91 

Cloverdale     227 

Coal   Canon    67 

Coast   Fire  Brick  Company 76 

Coast  Range    (see  under  various  counties  and  individual  ranges). 

Coe,  Ira  J. 137 

Colfax 135 

Color     248 

classification  of  clay  by 251 

common  names 249 

Munsell's  standards 250 

Ridgway's  standards   249 

Ridgway  vs.  Munsell 250 

variables  of 248 

Columbia  Cement  Company 85 

Colusa 71 

Colusa  County 70 

clay  resources 71 

bibliography    71 

Common  brick,   manufacture  of.   in  California 26 

(Common  brick  clay,  definition  of 15 

occurrence   of,   in   California 17 


300  iNDT':x 

Page 

Common   hrick  plants 21 

Conduct omoter    211 

Conduits,  clays  s-uital)Ie   for 255 

electrical,  manufacture  of,  in  California 27 

Cones,  pyrometric,  end  i>oints  of 244 

use  of,  in   softening  point  determination 246 

Conger,   A.   A.    105 

Contra  Costa  County 71 

clay  resources 72 

extinct  companies , 76 

geology   _ 71 

Cook,   T.    P.    121 

Coors,   H.   F 100,  194,  260,  264 

clay  in  Hart  Mountains 194 

tests  of 264 

use   of 100 

Coors,  H.  F.,  Company,  Inc. 100 

Core  drilling,  on  Arroyo  Seco  Grant 52 

Corning 231 

Cornish    stone    95 

Corona    (see  also  under  Alberhill) 162,  169,  179 

Corral  Hollow 42 

Costello,  F.  A. 39,  128 

Costs,  mining  and  transportation  of  clay 21 

Cosumnes  River 182,  185 

Cotati    227 

Cottonwood    223 

Coyote  Creek 139 

Coyote  Creek   (Santa  Clara  County) 219 

clay    219,  220,  221 

Coachella   Valley    84 

Crampton,   J.  T.    119 

Craycroft,   F.   J.    78 

Craycroft  brickyard    (Modesto) ; 229 

Craycroft -Herold  Brick  Company 78 

clay,   Merced   128 

Creegan,  J.  F. 39 

Crescent   City    76 

clay,  tests  of 326 

Cretaceous 18,  38,  64,  72.  73, 

79,  127,  139,  141,  161,  191,  200,  207,  213,  215,  217,  219,  225,  226,     229,234 

(Slee  also  under  Chico  formation.) 

Crucibles,  graphite,  clavs  suitable  for 254 

Cubach,  O.  J. 104 

Cummings,   C.   E.    72 

Cummings,   .T.   H.    229 

Cummings  Ranch 229 

clay    229 

tests  of 349 

Curran,    .James    89 

Curtis,  T.  S. 121 

Cutter,  George 185 

clay  on  pronertv  of 185 

tests  of 274 

Cuvamaca    Range    199,  200 

Cyanite    - -- 19,    29 

Imperial  "Valley,  deposit  of 86 

use  of 121 

D 

Davenport    222 

Davies,   J.  I.,.   111 

Davidson,    Nathan    100 

Davidson   Brick   Company   100 

clav.   tests  of 340 

Death  Valley S7 

clay,    tests    of    316 

Decoto,  plant  at 41 

Deformation   point    (see  softening  point). 

Dehesa,  Cornish  stone  at 95 

Del   Norte   County 76 

clay  resources 76 

Dempsey,  .1.  F. 23.5 

Demp.sey  Ranch    235 

c'ay,  tests  of 313 

Density,  apnarent 246 

Deutschke  Hill   (see  .lones  Butte). 

Diablo   Range    129,  191 

Diamond  Brick  Company "''- 

Diasoore 20 

clay,  classification  and  use 254 

'Diatex' 211 

Diatomaceous  earth  30 

Dickey.  N.  A.  40 


INDEX  307 

I 'age 

Uiokoy,  W.  S.  Clay  Manufacturing  Company 40 

li>ne   clays    58 

tests  of 281) 

Xiles  clay,   tests  of 34:5 

use  of   39,     40 

Plant   at    hivermore 40 

Plant   at    Niles 40 

iMlltiian.  M.  .1. 155 

Dirty-white-burning  clays,  tests  of 348-352 

Dosch  jiit    (lone)    58 

clay,  tests  of 302 

similar  clay,  tests  of 274 

Douglas,   K.   A.    118 

Douglas   pit    17G 

Drain   tile,   clays  suitable   for 255 

Drain   tile,  manufacture  of,  in  California 2G 

Drier,  Carrier 27,  107,  209 

Dry  transverse    strength    240 

Dry   press 28 

Dry-pressing    16 

Drying,  methods  of 17 

Drying  of  test  pieces 239 

Ducor    231,  232 

Dumortierite,  in  Imperial  County 86 

Duncan  Mills 226 

Durant,  Edward 215 

Durbin  Ranch 67 

■Durox'    121 

IHirst  Ranch 236 

Dwyer,   W.   P. 188 

Over's  Brickyard 123 


Karthenware,  red,  manufacture  of,   in  California 30 

East  Belt    (Mother  Lode) 68 

Echstine,  Mrs.  G.  P. 132 

clay  deposit 132 

Eckland,   Mrs.  C.   59 

clay   59 

tests  of 299 

Edgar  kaolin   (Florida),  tests  of 265 

(.See  also  under  Florida  clays). 

Edwin  clay,  tests  of 272 

Eel  River 79,     82 

El  Cajon   Mountain 200 

clay  deposit 201 

tests 259 

El  Centro 83,    86 

Electrical  accessories,   manufacture  of,   in  Calif()rnia 30,  40,  100 

Electrical   insulators,   manufacture  of,   in  California 30 

Electrical   Porcelain  Works 40 

Elk  Valley 77 

clay,  tests  of 326 

Elsenius,   C.  A. 49 

Elsinore    162 

Elsinore  Joint  Property 181 

El   Sobrante  property   181 

El  Toro 19,  140 

clays,  use  of   (see  al.so  under  Hunter  Ranch) 101 

Emeryville    (.see  Oakland). 

Emijire  China  Company 30,  101 

Emsco  Clay  Company 169 

clays    171 

tests  of 272,  278,  323,  328 

use  of 95,  97,  101-103,  111,   118,  119,  123 

Emsco  Refractories  Company 101 

Enameling,   metal,   in   California 30 

English  clays 28 

tests  of 257 

use  of 40,  45,  94,  95,  99,  100,  107,  109,  117,  123,  215,220 

Eocene 18,  42,  45,  64,  139,  140,  161,  162,  200,  202,  217,230 

Epperspn,   Mrs.   H.  T.   38 

Escondido 199,  202 

clay,  tests  of 348 

Etna    Mills   224 

Eureka 79,   80,     81 

Eureka  Brick  and  Tile  Company 80,   81 

Eureka  clavs,  tests  of 326,  336,   342 

Exeter 232 


368  INDEX 

F 

Page 

Face  brick,   clays  suitable   fur 253—256 

manufacture  uf,  in  California 2(j 

Face  brick  clay,  detinition  of 15 

Fairbanks,  H.  W. 84,  140,  199,  200,212 

Fairbanks,  R.  J. 88 

clay  deposit 88 

Fancher  pit    (lone)    58 

clays,  tests  of 280 

Farr  Siding 203 

Faulstick  Brothers 213 

Fawcett,  W.  R. 109 

Feather  River    (see  under  various  counties). 

Feldspar 19 

Arizona 28 

San  Diego  County 201 

use  of 28,  30,  40,  45,  46,  94,  95,  100,  101,  109,  117,  123,  215,  220 

Fernando    formation    234 

Ferrario,   B.  F. 73 

Field,  Thomas,  Ranch 131 

clay  from 131 

Field  tests 237 

Field  work 12 

Fillmore 233 

Findley,  Stuart 97 

Fineness  test 241 

Fireclay,  definition  of 15 

Fireplace  tile,  manufacture  of,  in  California 28 

Firing,  methods  of 17 

Firing  shrinkage    245 

Firing  treatment    (in  tests)    242 

Fish    Mountain    84 

Fisk,  H.  G. 243 

kiln    243 

Flint    fireclay    141 

tests  of 238,  282 

Floor  tile,  clay  suitable  for 255 

manufacture  of,  in  California 28 

Flores,    Ramon    144 

Florida  clay,  tests  of 257,  265 

use  of 28,  30,  40,  94,  95,  101,  109,  117 

Flournoy    231 

Flower  pots,  clays  suitable  for 255,  256 

manufacture  of 98 

Flue  lining,  manufacture  of,  in  California 28 

Forestville    227 

Forget,  A.   J.   85 

Fort  Jones 224 

Fortuna 80 

Foster,  A.  J. 188 

Franciscan  formation 38,  71,  76,  79, 

91,  124,  125,  126,  127,  129,  130,  132,  191,  207,  212,  215,  217,  219,  226,  229 
Freight   rates    21 

Alberhill  to  Los  Angeles 93 

Freshwater  Slough  clay 80 

tests  of 342 

Fresno     78 

Fresno   County    77 

clay  resources 77 

Full    Moon    clay   85 

Furnace    (see  under  kiln). 

oxy-acetylene    246 

Fusion  point   (see  softening  point). 

G 

Gabino  Caiion 145 

Gage  pit   (lone)    52 

clay,  tests  of 273 

Gamble,  H.  M. 65 

Canister,  deposit  of 194 

use   of 97 

Garber,  H. 141 

Garber  Brick  and  Tile  Company 141 

Garden  City   Pottery  Company   219 

Garden  Pottery,  manufacture  of,  in  California 27 

Garden  Ranch 67 

Gardner,   Harvey   174 

'Gasco'  brick 209 

Gavilan  Range 129,  130,  191 

Gaylord,    Ed.    159 

Gazelle    224 

Georgia  clay,  use  of 46 

CJerlack  Brick  Company 76 


INDEX  36!) 

Page 

German  fireclay,  tests  of 297 

use   of   97 

Oil)l)Kite    20 

Oilroy    219,  220 

Gilrov  Brick  and  Tile  Company 220 

Gin.nx,   R.    C.    42,  221 

GlarUling,  A.  L. 151 

Glacldinp,  Charles 152 

Gladding.  MoBean  and  Company 101,  141,  151,  171,  195,  202 

Alberhill  clays 171 

tests  of 91,  265,  272,  279,  289,  290,  298,  300,  311,  312,  323,  324 

Alberhill  plant 173 

Bryman  clay  deposit 195 

tests  of 314 

Cardiff  clay  deposit 202 

tests  of 322 

clay,  use  of,  fmm  Durst  Ranch 23fi 

from  Oroville 64 

from  Titus  deposit 90 

Klsinore  Joint  Property 181 

Goat  Ranch  clays 141 

tests  of 282,  330,  343 

Inyo  County  clay 88 

Lincoln  clavs _      152 

tests  of 299,   304,  325 

Lincoln   plant    151,  153 

Los  Angeles  plant      101 

Santa  Monica  plant 102 

clay,   tests  of 341 

Temescal  Tract 173 

Tropico    plant    102 

Glass  pots,  clay  suitable  for 254 

Glass  sand 20 

Glazing 17 

Glenbrook 91 

Glendale   102 

Glen   Ellen    227 

Glen  wood    222 

Glenn   County   79 

Globe  Tile  and  Porcelain  Works 103 

Goat  Ranch 19,  141 

clay,  tests  of 282,  330,  343 

Golden  Gate   Sandstone  Brick  Company 76 

Goldman,    M.    128 

Goodner  volumeter 239 

Goodyear.   W.   A.    199 

Goodyear  Station 225 

Gorda    1^0 

Gorge,  clav  near 159 

Goss.  H.  F. 189 

Gotham.  T.  B. , 215 

Grass  Valley 135 

Gray.son ??9 

Greenbrae     126 

Green  view     2?4 

nrejre.  J.  N. 223 

Griffith.   A.  "W. 142 

r;rimp<^.   H    H. 67 

Grog,  function  of If! 

Grog  pit.  near  Tone 61 

nros-Aimerode  fireclays 19,  200,  202 

GuadaUm«»    217 

Guerneville 2^6 

Gwin  Mine '^8 

Gypsum 141 

H 

TT  .Sr  H  Tile  Companv 103 

Kaaker.  C.  M. 140 

■FTaErerman.   Ord.    103 

TTalieman.  V.  K    103 

TTnmilton  cl'^v  deposit 90 

Hammond    W    J. 229 

TTnnoork.  C    P..  and  Son 181 

TTancock's   Brick  Tard    l^^l 

Hanford    90,  91 

Kanifv   Lumber  Company   R2 

TTarbor   City    105 

TTardnes« 248 

Waropnd'^fr  Mi"e   (see  Valley  View  Mine). 

Warrie.   Edwo»-d.    .Tr.      . 203 

Harrington  pit    (sre  Em.sco  Clay  Company). 

24—54979 


:]10  INDEX 

Page 

Hart 193,    194,  190 

clays,   tests  of 264 

use   of 117 

Harvey,    Fred    63 

Harvey  pit    (lone)    (see  Yosemite  Portland  Cement  Company). 

Hasty,  T.   \V. 78 

Havner,  H.  A. 105 

Haverstick,    Wm.    59 

clays,   tests  of 262,  263 

Hayden  Hill 92 

Haves,   H.   (}.   232 

Healdsburg    227 

Heins    Lake   clay    132 

Helisma    clay    68 

tests  of 305 

Hernandez    191,  192 

Hicks,  clay  near 195 

tests  of 288 

Hicks,    ganister    near    97,  194 

Hidecker,    G.    C.    41 

Hidecker  Tile  Company 41 

clay,   from  Marin  County 126 

High-grade  ceramic  pi-oducts 21 

Hill,   H.   C. 121 

Hill,   J.   H. 12,    162,  165 

Hill,   J.    M.        130 

Hislop,  J.  W.,  L.  J.  and  W.  A. 72 

Hoff,   J.   D.   174 

clay    property    174 

Hog  Mountain-Gopher  Range 68 

Hoist  pit 178 

Holland   Sandstone   Brick   Company    76 

Holliman,  R.  H. 195 

Holliman  and  Murphy  clay 195 

tests  of 349 

Hollister 190,   191,  192 

Hollow  tile    (or  block),   clays  suitable  for 255,  256 

manufacture   of,   in   California    26 

plants    --21 

statistics   31 

Holt  and   Gregg 223 

Horner,   E.   H.    209 

Hoskinson,  J.  P. 70 

Houts,  W.  A. 69 

Howeth,   H.    B.    119 

Hoyt,  W.   S.   73,     74 

Hudson  Ranch  clavs,  tests  of 315,  341 

Hue    248 

Humboldt  Clav  Manufacturing  Company 80 

Humboldt  County 79 

clay  resources SO 

geology    1 79 

Humboldt  State  Teachers  College 80 

Hungry  Hollow 80 

Hunter  Ranch 19,  140 

clay    140 

tests  of 260 

use   of   96,  101 

Huntington  Beach 143 

I 

Idria    191 

Illinois  silica 28,    30 

use  of 45,  46,  215,241 

Imi>erial  County 83 

clay  resources 85 

cyanite  and  dumortierite 86 

geology    83 

mineral    resources    85 

physiography 83 

Independent  Sewer  Pipe  Company 171 

Inglewood     100 

Insulators,   electrical,  manufacture  of,   in  California 30 

Insulators,   thermal,  manufacture  of,   in  California 30 

Inverness    124 

Inyo   County    87 

clay  resources 88 

geology 87 

lone   — -   49-  63 

clay    use  of 40,  41,   97,  117,  128.  209,  215,  216,  220 

sand,  use  of 39-42,  46,  49,  72,  74,  75,  94,  183,  187,  221 

use  of  in  cements 51 


INDEX  ,S71 

Page 

Iiin»'  Fin-  Hriek  Company 60 

sand 55,    61 

tests  of 280 

lone  formation 19,  50,  64.  67-69,  128,  146,  147,  183,  185,  223,230 

Iris  Pass 84 

Irving,   n.   H. 13 

Irving,  F.  M. 74 

Isitt,  R.    P. 119 

Italian  Terra  Cotta  Company 103 

J 

.lalanivich  and  Olsen 207 

Janiiesen,   J.   J.   221 

Jenkins,  R.  H. 80,     81 

Jenny  Lind 68 

.lens  deposit 132 

Johanson,    Gustav    187 

Johnson,  C.    P.    103 

Johnson,   H.   K. 188 

Johnson,  I.   J.    223 

Jolon    130 

Jones  Butte   (lone)    53 

clays,  tests  of 272,  302,  328 

Jurassic 50,  79,  139,  215,  217,  229,234 

(See  also  under  Francisf-an  formation.) 

K 

K  &  K  Brick  Company 104 

K  &  M  Pottery 104 

Kales,  F.  A. 76 

Kaolin,  definition  of 15 

resources  of,  in  California 20 

'Kaospar'    95 

Kartschoke,   G.    220 

Kartschoke  Clay   Products  Company 220 

Kaspe,  A.  H. 89 

Keeler,  F.  E. 96 

Keeler,  R.  B. 107 

Keenan,  J.   F.   203,205 

Kelch,   Martin   229 

Kelley,   Thos. 94 

Kelley  Ranch  clays 203 

tests  of 296,  322 

Kelseyville   91 

clay   92 

tests  of 336 

Kennedy,  J.  J. 194,  195 

Kennett 223 

Kentucky   clav    28 

use  of 46,   94,     95 

Kern  County 88 

clay  resources 89 

Kern  County  Brick  Company 89 

Kieffer,  S.  B. 12,  51,  52,    63 

Kildale,   M.   B. 81 

Kiln,   Calkins   39,      45 

field    26 

Haigh    40 

Hoffman 42,  74,  105,   125,  208 

round  down-draft 26,  27,    29 

test     24  2,  243 

tunnel 28,  29,  30,  216 

Harrop    96,  123 

King,  Elmer 89 

King,  J.  B. 220 

King  Lumber  Company   89 

Kings   County 90 

clay  resources 91 

bibliography 91 

Kitchenware,  manufacture  of,  in  California 30 

Knemeyer,    C.    V 121 

Kraft,  C.   H.  and  J.  L. 41 

Kraft  Tile  Company 41 

Krause,   F.   C.   144 

Kremer,  Victor 99,   109,   201,  205 

Kummer,    George    205 

L 

La  Bolsa  Tile  Company 142 

Laboratory   tests    238 

La  Cal  Tile  Company 104 

Lacv,  Roy 116 

Lacy,    William    109,  203 


372  INDEX 

Page 

I^adrillo     204 

Lagomarsino,    J.    J.    122 

Laguna    Hills    139,  140 

Laguna  Mountain  Range 199,  200 

Laguna    Seco    Grant    131 

Lagunitas 126 

Lagunitas  Development  Company 126 

Laizure,  C.  McK. 12,   13,   73,   74,   76,  79,  190,  225 

LaJolla 200 

Lake  County 91 

clav  resources 91 

Lakeside     201 

Lanoha   Plana 50.     68 

Landis,  Judge  J.  B. 159 

Lane  mottled  iiit  (lone) 57 

Larsen,  Gustav 100,  105,  174 

Las  Encinitas  Ranch   202,  205 

Lassen   County   ^ 91 

clav  resources 91 

Lassen  Peak 230 

Laterite 53,    54 

tests  of 328 

Lawson,  A.  C. 124 

Lead  pots,  manufacture  of 39 

Leash,   H.   E.   41 

Lignite   (see  under  lone). 

Lincoln 146,  147,  151,  155,  159 

clay,  general  properties  of 147 

use  of 39-42,  46, 

49,  60,  72,  74,  75,  94,  97-99,  103,  111,  117,  118,  153,  183,  187,  209,  219,  221 
Lincoln  Clay  Products  Company 158 

clays    155 

tests  of 291,  298,  303,  336 

Lincoln,  Earl 117 

Lincoln  Heights   111 

Linda  Vista  clay 205 

tests  of 322 

Linderman  and  Decker  Company 104 

Lindgren.  Waldemar 64,  135 

Linton,  Robert 109,   176,203 

Livermore  Firebrick  Works   (see  W.  S.  Dickey  Clay  Products  Company). 

Livermore  Valley 38 

Llanda 191 

Logan,  C.  A. 12,  13,  50,  51,  61,  67,182 

Lomita 104 

Lompoc 217 

Long  Beach   Brick   Company   105 

Loofbourrow,  Dr.  T.  L. 80 

clay 80 

tests  of 342 

Los  Angeles  Brick  Company 105 

Alberhill    property    174 

clavs    175 

plant    176 

Chavez  Caiion  Yard 105 

clays,  tests  of 278,  279,  281,  288,  289,  297,  298,  300,   315,  335 

Mission  Road  yard   105 

Seventh   Street  yard    107 

Los  Angeles  County 21,    92 

clay  resources 17,    93 

Los  Angeles  Pottery   Company    90 

Los  Angeles  Pressed  Brick  Company  (lee  Gladding,  McBean  and  Company  ;  also 
Richmond  Pressed  Brick  Company). 

Los  Burros  district 1-^0 

Los  Nietos 114 

shale,  use  of 1 1  f* 

Los  Olivos    217 

Los  Pefiasquitos  Canyon   200 

Lovelocks ^'^ 

Lund,    Nelson    E.    ^^ 

Lund  Brick  Yard ^5 

clay,  tests  of 325 

M 

M  &  S  Tile  Company 41 

clay,  tests  of 343 

Madera 123 

Madera    County    123 

clav    resources    123 

Maeden   W.   T.    192 

Magnesia  brick 21 

■Maenesium  oxide ''21 

Mahan,    N.   J.    219 

Maillard   Ranch    126 


INDEX  373 

Page 

Malibu    Potteries 107 

Malibu   Kanch 9-^.  10( 

Maiiufactiiring  Methods Ifj 

ill  California  plants 26 

.Maiizanita   Mine  clay 136 

tests   of ■^4^ 

Marl)l<hea(l   Land  Company   1''7 

.Marin   County 123 

flay  ri'siiurres l^'^ 

earlier  reports ,- 120 

bibliography    12  •> 

geology 124 

Mariposa    formation    ov,  os 

Marsh,  C.  L. 133 

Martin,   M.   A. l^f 

Martin  Ranch  (Carmel) 1^1 

Marysville    23() 

Marysville  Brick  Company 23() 

Marysville    Buttes    230 

Massey,   Crawford    95 

Mastercraft  Tile  and  Roofing  Company J3 

McBean,    Atholl    101,  151 

McCarthy,  P.  O. 203 

McClathy.  H.  J.   189 

McClintock,  C.  V. 114 

McClintock,   Earl    9° 

McClintock,   Wm. 109 

McKissick   Cattle    Company    ol,  63 

McKnight  Fire  Brick  Company 232 

McKnight    pit    I" -^ 

clays,  tests  of ^^^ 

McNear,  K.  B.  and  L.  B. 124 

McNear   Brick   Company    124 

clay,  tests  of 329 

McNear  Point 124 

Melvin,   II.   D.   220 

Mendenhall,  W.  C. °4 

Mendocino    126 

Mendocino  County 126 

clay  resources 12" 

Mendocino  State  Hospital 126,  127 

Merced    127.128 

clay  near,   use  of ]^° 

Merced  County 127 

clay  resources 127 

bibliography 12-' 

Merced  Falls 1'''' 

Mero,  C.  V.  and  F.  A. 73 

Merrill,  Dr.   F.  J.   H. 199 

Merry  Widow  Mine 90 

clay,  tests  of 349 

Mesmer,  A.  J.,  and  Joseph 118 

Mesozoic 87,  200 

Michigan  Bar  clays 185 

tests  of 273,  274 

Middle    Bar    50,  68 

Mid   Hills 195 

Millbrae    215 

Miller,    K.    A.    99 

Miller's  Oakland  Art  Pottery 41 

Millett,    M.    J.    195 

clay    195 

tests    of    288 

Milton    68 

Mining  (sec  also  under  descriptions  of  clay  pits). 

methods  in  California 20 

Minner,  V.  J. 13 

Miocene 45,  73,  80,  105,  132,  161,  193,  200,  215,  217,  219,  222 

Mission  Brick  Company 107 

Mission  China  Company 109 

Cardiff    clay    201 

Mitchell,  W.  C. 203 

Modesto 229 

Modulus  of  rupture 240 

Mojave  Desert   (see  Kern,  Riverside  and  San  Bernardino  counties). 

Mokelumne  Hill   68 

Mokelunine    River    182 

Molding    (see  shaping). 

Montalvo    233 

Montecito 218 

Monte   Rio 226 


o74  INDEX 

Page 

Monterey  County 129 

clay  resources 130 

bibliography    132 

geology    12!t 

Monterey  formation 124,    139,140 

Monterey  Mission  Tile  Company 131 

clay,  tests  of 327 

Monterey  Park 120 

Moore,  G.  W. 142 

Morris,  H.  T. 202 

clay    202 

tests  of 348 

Mother  Lode 50,  fi8 

Mt.  Diablo  Pottery  and  Paving  Brick  Company 7fi 

Mount  Diablo  Range 229 

Mount  St.    Helena    227 

Mount  Sam  Quicksilver  Mine 91 

Mount   Whitnev    87 

Muddox,  H.  C. 1S6 

Muddox  Pottery 186 

IVruengenberg.  R. 218 

Muengenberg  and  Whitiker 218 

clays    218 

tests  of 338 

Muir,  "SVm.   F. 42 

Mulford,  William 203 

Mullite    29 

manufacture    of    121 

Munsell,   A.   H.    248 

Munsell  color  standards 250 

vs.  Ridgway  standards 250 

Muresque  Tiles,   Inc.   42 

Murphy,   D.   195 

Murphy,  E.  W. 105 

Musick,   property    77 

clay  (No.  180),  tests  of 32fi 

Myers,  A.,  clay 41 

Myers,  M.  C. 104 

N 

Nacimiento  River 129,  130 

Napa     132 

Napa    County    132 

clay    resources    132 

bibliography 135 

Napa   Junction    132,  133 

Napa  Valley   132 

National  Brick  Company 203 

National    City   203 

Natoma   Clay   Company 185 

clay,  tests  of 337 

use  of 41,  fi4,  128,  221 

Neocene 68,   135,  136 

Nevada  china  clay,  use  of 19,  30,  101,  123 

silica    28 

Nevada   City   135,  136 

Nevada  County  135 

clay    resources    135 

bibliographv 139 

New  Almaden 219 

New  Idria   mine 191 

Newman     229 

Newman  Clay  Company 63 

(See  also  under  Newman,  May  E.,  Estate.) 
Newman,  May  E.,  Estate 61 

clays,  tests  of 329 

sand,   tests   of   261,  290 

Newsom,  J.  F. 222 

New  York   Mountains 195 

Nigger  Hill  clay,   tests  of 263 

use  of 39 

Niles    40 

clay    40 

tests  of 343 

use  of   39,     42 

Xlles    Valley    38 

Xoniilastics    19 

North  Bloomfield  Road  clay 136 

tests  of 329 


INDKX  ;5T") 

O 

rage 

Oakdale     22!t 

Oakland,  day,  use  of Vu"i^"l9     H 

plants  in 3S»,   41.   42,     45 

Oak  Run ^^^ 

OCarroll.  H.  J. 13 

Oceanside   *^^ 

Ockernian,   K.   H.   ^* 

O'Connor  Brothers  Brickyard f^l 

Odin   Mine    }36 

ODonnell,  Dr.  J.   M. — --    192 

Ogilby ^Sf^'97i 

Qjai    m,  i-i^ 

Old   Mission  Portland  Cement  Company 1-J2 

Old  Mission  Tile  Company 203 

Oleta 50 

Olive    l*!'  1** 

Olive  Roofing  Tile  Company \j^f 

Olivenhain    ■^"'5'  -^"^ 

Ollas.    manufacture  of   ^° 

O'Xeill,  Jerome Ij^ 

O'Neill  Ranch  clay ^jy 

tests  of f:?; 

Orange  County !.-y' 

clay  resources f^y' 

bibliography j^^ 

geology    \-l^ 

Orange  County  Brick  and  Tile  Company i^o 

Oi-i(.l{ '■' 

Oroville,  clay  deposits  and  plants  near --;     64 

clavs,  tests  of •^'^=''  •'•'^ 

Orpin,  Chas. *^ 

Ortman,  F.  B. '"J 

Orton  standard  cones,  end  points  of ^^2 

Osmont,  V.  C. MA,  iib 

Ottawa  sand    (see  Tllinois  silica). 

Owens  Brick  Company    (see  California   Brick  and  Tile  Company). 

Oxnard    ;^^ 

Oxy-acetylene  furnace ^*" 

P 
Pacific  Clav  Products  Company   109 

^""cll^ys^^^of  ^  --::::::::::::::::::::::::::::::ii^:^i:-^:2^i:^^.  32^ 

Douglas   pit    \ll 

Hoist  pit Yl 

McKnight  pit ]Y 

Miscellaneous    properties    '"" 

Kelley  Ranch  clays -  {"^ 

tests  of ^^'°'  ^f^ 

T.,incoln   Heights   plant    ']* 

I.,os   Nietos   plant    ''^ 

SUnison  Avenue  plant 'Jjj 

Wildomar  property   l^" 

Pabricr),    plant   at    *' 

Pacific  Art  Tile  Company  (see  C.laddin,  McBean  and  Company). 

Pacific  clay    l"^ 

Pacific  Minerals  and   Chemical   Comnany »» 

(Hee  also  Oladdine,  >TcB<-nn  and  Company.) 

Pacific   Portland  Cement  Coinpanv   (foot  note) ^^ 

Pacific  Sanitary  Manufacturing  Company  (see  Standard  Sanitary  Manufacturmg 

Company). 
Pacific  Sewer  Pipe  Company    (see  Pacific  Clay  Products  Company). 

Page,   Charles IJ 

Pagliero,  J.    '^ 

Paicines  clay '2i 

tests  of "'J' 

Paine,    R.    E.    \l 

Pajaro  River {^" 

•Paiacio'  tile  „--:;7""oV";;;  ,no 

Paleozoic 79.   84,  87.  161.193 

I'alermo,  brick  yard  near ^^ 

Palo  Alto 21H 

Palo    Cedro    •^-'j 

Palo  Verde  Mountains   ^^ 

Panama  Pottery 1°^ 

Pardee,    J.    E. „%i 

Parmelee,  C.  \V. 241,  253,  254,  255.256 

Parsons,  'w.    E.    1;'^ 

Paso    Robles    212 

Patent   Brick   Company    1^^ 

Patterson    229 


376  INDEX 

Page 
Paving    brick    18 

Clays  suitable  foi' 2ou 

Peardaie     ia5,  138 

i'encils,  clays  suitable  for 2uu 

I'enn    iMining    Company,    clay VO 

tests  of 31G 

Pentz    64 

People's  Lumber   Company 234 

clay    234 

tests   of 338,  339 

Petaluma    22 G,  227 

Philadelphia  Quartz  Company uO,     (i3 

Philo,  b\  A. ys 

Picacho  Hills , 84 

Pike,   11.   D.    211 

Pilot  Knob 83 

Pine  Hill  Mine 137 

clays     137,  138 

tests  of 261,  315,316 

Pine  Mountain   233 

Pinnacles    130,  191 

Pioneer  Brick  Company 232 

Pioneer  Brick  and  Tile  Company 78 

•Pipe'   clay 136 

I'ismo    212,  213 

Pit  River 222 

Placer  County 146 

clay  resources 146 

Lincoln    district    147 

miscellaneous   deposits    158 

Plants,   clay-working,   of  California   21 

(See  also  under  company  names.) 
Plasticity,  nomenclature  of 239 

water    of    239 

Piatt's  Premier  Porcelain,   Incorporated 220 

Pleasanton,  plant  near 42 

Pleistocene 18,   139,   200,  202 

Pleyto     132 

Pliocene 64,  91,  161,  215,  217,  219,  222,  234 

Plumbing  accessories,  manufacture  of,   in  California 30 

Plymouth    50 

Point  Loma 200 

Point  Reyes 124 

Point  Richmond 74 

Pomona    116,  117 

Pomona  Brick  Company   116 

Pomona  Tile   Manufacturing   Company 117 

Porcelain,  clays  suitable  for 253,  254 

Porcelain  insulators 46 

Porcelain  plumbing  accessories • 100 

Pore    water    240 

Porosity,  apparent 245 

Port  Costa 73 

Port  Costa  Brick  Company 73 

clay,  tests  of 326 

Porterville    232 

clays,  tests  of 327 

Pottery,  clays  suitable  for 253,  254 

Pottery  clay,  statistics 31 

Poxon,  G.  J. 117 

Poxon    Pottery    117 

Power,   M.   I. 97 

Prado  Tile  Company 181 

Pre-Cambrian   79,   84,   161,  193 

Preston,  W.  A.,  property 81 

Prices,  clay 21 

'Promenade'  tile 102 

Prouty-line  Products  Company  (sec  American  Encaustic  Tiling  Company,  Ltd.). 

Providence  INIountains 195 

Prussing,  Henry 100,  105 

I'yrometric  cones,  end  points  of 244 

I'yrometric   control   of   tests   243 

Puente  formation 105 

Pullman,  V.  T. 120 

Q 

'Quarry'    tile    101,  102 

Quartz  sand  (see  also  under  silica) 20 

lone 51 

Tesla   45 

Quartzite    19 

Quatenary__64,  76,  79,  80,  84,  85,  91,  92,  127,  161,  191.  193,  207,  213,  217,  219,  227,   231 

Quincy  Road  clays,  test.s  of 325,  336 

Quintet   property    ISO 


INDEX  377 

R 

I'age 

Radiant  stove  backs 90 

liuiK-ho  Arroyo  Seco   {see  Arroyo  Seco  Grant). 

Kaniho  tU-l    I'aso ._    183 

Uanoho  de  Santa  Margarita    (stc  O'Neill  Ranch). 

Jtatio,   pore   to  .shrinkage   water 240 

Itaymond,   P. • 219 

Red  Hluff 2;{1 

Red-burning  clays,  tests  of 321,  352 

Reddick   .Mine   130 

Redding    222,  223 

Redding  Brick  and  Tile  Company 223 

Redding  Grant 223 

Redding  Homestead ^_-   223 

Reed,    T.    H.    120 

Reed  Tract 231 

Reeves,  \V.  N. 94 

References,  general   13 

Refractories,  clays  suitable  for 253,  254,  255 

manufacture  of,   in  California 29 

tests  of 243 

Remillard,    C.    42,  221 

Remillard  Brick  Company,  Greenbrae  property 120 

Pleasanton   plant 42 

San  Jose  plant 221 

Reordan,   \V.   C.    100,  106 

Reseda 97 

Retorts,   zinc,  clays  suitable   for 253,  254 

Reutera,  J.  F. 107 

Rice,   J.    W.    204 

Rice,    W.    D.    221 

Richard,  K   M. 13 

Richards,   R.   L.   221 

Richmond    1 72,    73,     76 

Richmond  Brick  Company 76 

Richmond  Pressed  Brick  Company 74 

clay,  tests  of 325 

u.se  of 39 

Ridgeway,  E. 41 

Ridgway,  Robert 248 

Ridgway  color  standards 249 

vs.    Munsell    standards 250 

Riley,  L.  F. 65 

Riverside    181 

Riverside  Brick  Yard   (see  Sacramento  Brick  Company). 

Riverside  County 161 

clay    resources    162 

bibliography 182 

geology 161 

Roberts,  F.  H: 100 

Roberts,  John  T. 13,  60,   147,  209 

Robinson,  W.  H. 103 

Robinson  Ranch 140 

Roffe,    \Vm.    203 

'Roman'  brick 183 

Roofing  tile,  clay  suitable  for 255 

manufacture  of,  in  California 27 

Rosamond    89,    90 

Rose  Canyon 203,  204 

Ro.ssi,  Ernest 208 

Royalty 21 

Rupture,  modulus  of 240 

Russ  Building - 27,  152 

Ru.ssian    River    226,  227 

Ryan,  J.  W. 45 

Ryan,    Wm.    45 

Ryan   Ranch   clay    45 

tests    of    263 

s 

S.  p.  Brick  and  Tile  Company 232 

S  &  S  Tile  Company 221 

Sacramento 182,   186,   187,  188,  189 

Sacramento  Brick  Company 188 

Sacramento  Clay  Products  Company   (see  Cannon  and  Company). 

Sacramento  County 182 

clay  resources 183 

bibliography 189 

SacraTnento  Navigation  Company 188 

Sacramento  River    (see  under  various  counties). 

Sacramento  Valley,  clay  deposits  in 17 

(See  also  under  various  counties.) 

Saggers,  clays  suitable  for 253,  254,  255 


378  INDEX 

Page 

St.  Louis  Fire  Brick  and  Clay  Company 118 

Weiss  clay,   test  of   227 

Salinas  Valley 12y 

Salmon  Creek 226 

Salton  Sea 83 

Salt  Spring  Vallej' 68 

Samples,  list  of  tests  on  field ^ 258 

methods  of  taking  field 12 

preparation   of,    in    laboratory    238 

weight  of 238 

San  Andreas  fault 124 

San  Benito 191 

San  Benito    County    190 

clay  resources 192 

bibliography 193 

geology 190 

San   Benito   River 190,    191,  192 

San   Bernardino    County    193 

clay  resources 193 

bibliography 198 

Sand    Hills    83 

San  Diego 203,   204,  206 

San   Diego  County 198 

clay  resources 200 

geology   199 

San  Diego  Tile  and  Brick  Company 203 

clay,  tests  of 339 

Sand-lime   brick   144 

San  Emigdio  Mountains 233 

San  Francisco  Bay  district 21 

(See  also  under  various  counties.) 

clay  deposits   in    17 

San   Francisco  County 206 

San  Gabriel  Range 93 

Sanitary  ware,  clays  suitable  for 253,   254,  255 

manufacture   of,   in   California   30 

San  Jacinto   Range    199 

San  Joaquin  Brick  Company 208 

San  Joaquin   County 207 

clay    resources    207 

bibliography 212 

San  Joaquin  Valley   (see  under  various  counties). 

clay  deposits 17 

San  Jose 219,   220,221 

San  Jose  Brick  and  Tile  Company 221 

San  Jose  Range 212 

San  Jose  Tile  Company 221 

San  Juan  Bautista 191,  192 

San  Juan   Capistrano   19,  14.'i 

San   Ijorenzo   River   222 

San   Luis  Brick  Works 213 

San  Luis  Obispo 212,  213 

San  Luis  Obispo  County 212 

clay    resources    213 

bibliography 215 

San  Mateo   County    21.'i 

clay  resources 215 

bibliography 216 

San   Pablo    73,  76 

San  Pablo    Bay    225 

San   Rafael 124 

Santa  Ana 139 

Santa  Ana  Canyon    . in 

Santa  Ana  Range 139,  140.141 

Santa  Ana  River 139 

Santa  Barbara    217,218 

clav,  tests  of 338 

Santa   Barbara  County 217 

clay  resources 218 

bibliography 219 

geology  and  mineral  resources 217 

Santa  Barbara   National   Forest   215 

Santa  Clara     219,  220 

Santa   Clara  County 219 

clav  resources 219 

Santa   Clara  River 233 

Santa  Cruz    222 

Santa   Cruz  County 222 

clay    I't'soiu'ces    22'' 

bibliography 222 

Siinta  Crux  Moimtains 220 

Santa    Cruz  Portland  Cement  Company 222 

Weiss  clay,  test  of 227 


INDEX  37!) 

I'agu 

Saiitii   Lucia   Mountains 129 

SaiUu   lAuiu  liangf 212,213 

SaiUa    .MaiK'arita 212,  213 

clay  shale  near 213 

,  le.sis  of 327 

Santa  ^largarita,  Ranoho  de   (see  O'Neill  Ranch). 

Santa   Maria    217 

Santa   Maria  River 217 

Santa   Monica 93,  94,  102,  107,  118,  119,  122 

(Set-  also  under  Los  Angeles  County.) 
Santa   Monica  Crick  Conipany 118 

clay    102 

tests  of 341 

use  of 97,  98,  101,  102,  104,  117,  118,  119,  122 

Santa   Monica  Range 93 

Santa   Paula    233,  234 

clay,  tests  of 339 

Santa   Rosa    226,  227 

Santa  Rosa  Alountains 84 

Santa   Susana  Range 93 

Santa   Ynez  Mountains 233 

Santa   Ynez   River   217 

Santiago  Creek 139 

Saugus    233 

Sbarl)ori,  Louis 126 

Schenimel,  F.  P. 221 

Schrieber,   Mr.   95 

Schroeder,  R.  J. 117 

Schroyer,  C.  R. 241,  256 

Schutte,  C.  N. 13,   53,   147 

Sears,  W.  A. 232 

clay    232 

tests  of 282.    314,316 

Seaside    131 

Sebastopol    226,  227 

Sewer  pii)e,  clays  suital>le  for 255 

manufacture  of,  in  California 26 

Shade 249 

Shakers,  salt  and  pepper 38 

Shale,  common,  in  California 17 

Shaping,  of  clay  ware 16 

of  test  pieces 239 

Shasta   County    222 

clay  deposits 223 

Shepard   pit    (lone)    54 

sand,   tests  of : 261 

Shields,   H.   W.    232 

Shoshone     88 

Shrinkage,   drying    240 

firing   245 

Shrinkage,    water 239 

Sierra  Nevada   (see  under  various  counties). 

'Sierra'   roofing   tile 128 

Silica   (see  also  under  quartz  and  Illinois) 19,    28 

use  of 40,  94,  95,  100,  101,  109,  117,  123,  209,  215,  220 

Silica   brick    29 

Silica   (quartz),  San  Diego  County 201 

Simons.  H.D. 104 

Simons,  H.  W.,  J.  V.  and  R.  G. 120 

Simons.    W.    R.    86,  119 

Simons    (town)    119 

Simons  Brick  Company 119 

Boyle   plant    119 

El   Centro   plant   86 

Santa    Monica    plant    119 

clay  used  in 102 

Simons  plant 119 

Siskiyou  County 224 

clay  resources 224 

bibliography 224 

Sizing,    methods   of    241 

test,   Natonia  clay   338 

Skee.  Geo. 121 

Skyland 220 

Slip  clay,  definition  of 15 

Smart  sville     235 

Smith,   K.   M. 101 

Smith,    G.    L.    41 

Smith,  Mrs.  Mary  Y. 90 

Smith,   S.    W.   74 

Smith    River    76 

Snow   Ranch    67 

Soda  Bay 91 

Softening    point    246 


380  INDEX 

Page 

Soft-mud  .shaping 16 

Solano  County 225 

clay  resources 225 

bibliography 225 

Solon,  A.  I.. 221 

Sonoma    County    225 

clay  resources 227 

bibliography 228 

geology 22C 

Sonntag  Ranch  clay 135,  138 

tests    of    313 

Southern  Pacific  Company 223 

Southgate __99,  101 

Specific  gravity,  apparent 245 

true    246 

Stahlman,  E.  G.,  and  H.  F. 116 

Stammer,  H.  M. 219 

Standard   Brick  Company   120 

Boyle  Heights  plant 120 

Inglewood  plant   120 

Standard  Sanitary  Manufacturing  Company 75 

Pacific   Enamel  Works 76 

Pacific  Mine   (Hart)    196 

clays,   tests  of 264 

Pacific   Pottery 75 

Stanford  University 12,   252,  257 

Stanislaus  County 228 

clay  resources 229 

bibliography    230 

Starkweather,  G.  A. 52,  53,  54,  56,     63 

Statistics    31 

Steiger  Brick  and  Tile  Company 225 

Steiger  Terra  Cotta  and  Pottery  Works 215 

Stevenson  Engineering  Company 252 

Stiff-mud    shaping    16 

Stine,    I.    F.    208 

Stockton   208,  209 

'Stockton'    brick    209 

Stockton  Brick  and  Tile  Company 208 

Stockton  Fire  Brick  Company 30,  209 

Jones  Butte  clay    (c.   v.)    52 

Stockton   plant    209 

Stoneware,  clays  suitable  for 253,  254,255 

manufacture  of,  in  California 30 

Strength,    bonding   241 

dry    transverse    240 

Strong's  Station  Clay 81 

tests  of 342 

Structure    248 

Sulphur  Bank 91 

Sunset  Brick  Company 123 

Super-refractories    121 

Superstition    Mountain    83,     84 

Sur  River 129 

Surf 217 

Susanville 92 

Sutter  County 230 

clay    resources      230 

bibliography     230 

Sutter  Creek,  geology 50 

Svendsen,  C.  V. 117 

Sweet,  John 138 

clay  deposit 138 

T 
Table   Mountain   64 

Table  Mountain  Clay  Products  Company 65 

clay,  tests  of 304 

Tableware,  manufacture  of,  in  California 30 

Talc 19,     28 

Talc  schist,  deposit  of 194 

Talmage   126,  127 

Tank  Siding,  clay  at 222 

Tara's   Porcelain   Laboratory   207 

Taylor,   F.   M.    118,  136 

Teale,  W.  R. 133 

Technical  Porcelain  and  China  Ware  Company 42 

Tecopa    88 

Tehama   County   230 

clay  resources 231 

bibliography    231 

Tejon  formation 42 

Temescal  Sixty  property 181 

Temescal  Valley 18,  140,  ]r,2 


liNDEX  381 

I'age 

Ttnu'scal  Water  Company       181 

clay   (No.  218)   181 

tests  of 329 

Temperature  control   (see  pyrometric  control). 

Temperature,  firing,  range  of 16 

measurement  of 244 

Tennessee  clays,  use  of 28,215 

Terra  cotta,  clays  suitable  for 253,  254,  2r>r) 

,  manufacture  of,  in  California 2ti 

Terra  Cotta  Eighty  property 181 

Terra  Cotta  Plant  Site  property 181 

Tertiary 38,  50,  72,  73,  79,  80,  84,  85,  87,  91,  92,  93,  126,  127,  130, 

132,  135,  139,  158,  IGl,  191,  193,  139,  200,  204,  207,  213,  217,  225,  227,229 

Tesla   38,  207 

clay  deposits 42 

clay,  tests  of 2fi3 

Test  pieces,  drying  of 239 

molding  of 239 

Tests,    field    237 

laboratory    238 

list  of,  on  clay  samples 258 

Texas  Mining  Company 70 

clays,  tests  of 263 

Texture 248 

Thebo,   J.    85 

Thermocouples,  use  of,  in  tests 243 

Thermal  insulators,  manufacture  of,  in  California 30 

Thomas,  C.  R. 39 

Thomas.  F.  J. l\ 

Thompson,    J.    D.    80,     81 

Thompson  Brick  Company 81 

clav,  tests  of 326 

Tiffany,   Jas.    109 

Tile  Shop,  The 39 

Tillotson,  Clifford 97 

Tint 249 

Titus,  H.  E. 89 

clay  deposit °^ 

clay,    tests   of   ^12 

Tomales  Bay 124 

Tone   (color)    249 

Topatopa  Mountain 233 

Toro  Canyon 218 

Toro  Canyon  Brick  and  Tile  Company 218 

Toro  Canyon  Clay,  tests  of 338 

Torrance     J^^ 

Torrance  Brick   Company   120 

Plant  No.    1.    120 

Plant  No.   2 120 

Towle,  clay  near 1^^ 

Tracy   Brickyard    (Eureka)    |0 

Transportation,  methods  and  costs 20 

Transverse  strength,  dry 240 

Tremain,  E.  E. ion 

Tres  Pinos 190 

Trewhitt,  ^V.  D. ^^^ 

Trewhitt  Brickyard 91 

Triassic Ij^J 

Trinidad ^9 

Tronico ^  '''•  '    ' 

Tucker.  W.  B 12.  13,  82,  87,  92,     94 

Tudor  Art  Tile  Company 121 

Tudor  Potteries,  Inc.   (see  Tudor  Art  Tile  Company). 

Tulare    County    |^1 

clay  resources ^^l 

bibliography    23^ 

Turner,  Wm. 1° 

Tuscan  formation °' 

U 

Ukiah    126 

Underwood,   H.  V.   ^^^ 

Union  Brick   Company ^"* 

clav,  tests  of ^^" 

Union   Hill   ^ l^"! 

United  Materials  Coinpany ^* 

United  States,  clay  products  production  in ^•> 

University  of  California 


382  INDEX 

Page 
V 
Valencia  Heiglits  Khalt.' 232 

tests  of   (No.  20ti>    3a< 

Vallejo 225 

\'aIlejo  Brick  and  Tile  Company  (see  Steiger  Brick  and  Tile  Company). 

Valley  Brick  Company 189 

Valley   Ford     22ii 

Valley  .Spring.s 68,   69,     70 

clays,    tests    of    299,  337 

use   of 39,  128 

Valley  View   Mine   159 

clay    161 

tests  of 263,   328,350 

Value    (color)    249 

Van   Cleve,   Albert 41 

Vander  Leek,  Lawrence 226 

Van  Duzen  River 81 

Van   Nuys 99,    104,  107 

Van   Vleck  and  Sons 185 

clay  on  property  of 185 

tests  of 273 

Ventura    233,  234 

clays,  tests  of 338,  339 

Ventura  County 233 

clay  resources 234 

bibliography 234 

geology 234 

mineral  resources 234 

Ventura  River 233 

Vernalis    207 

Vidal    181 

clays,  tests  of 340 

Vincent,  M.  L. 121 

Vitrefrax  Company,   The 29,  121 

Ogilby  cyanite  deposit 86,     87 

O'Neill   Ranch   fireclay   145 

tests    of 259 

Vitrified  Product.-?  Corporation 205 

Cardiff    clay    205 

tests  of 287,  288 

Linda  Vista  clay 205 

tests   of 322 

San  Diego  plant 206 

Volcano     50 

Volumeter    239 

Volume   measurement   239 

W 

Wall,  J.  A. 45 

Wall  tile,  manufacture  of,  in  California 28 

Wallace,  D.  W.  and  L.  F. 221 

Walnut   Creek  shale   73 

tests  of 342 

use   of 40 

Walrich  Pottery 45 

Walters,  C.  J. 97 

Walters,   W.  J.   89 

Ward,    Henry    68 

Warfield    227 

T\^ashington  Iron  Works 122 

Water  of  plasticity 239 

Water,    pore    240 

Water,  ratio  of  pore  to  shrinkage 240 

Water,  .shrinkage 239 

Waterford    229 

Watson,  H.  L. 131 

Watts,   A.   S.    241 

Weatherhy  Ranch  clay 82 

Webb,   W.    S 90 

AVeed,  C.  H. 232 

Weibling 143 

Weiss,  Henry 21.'> 

Weiss,  J.  H. 227 

clay   227 

tests  of 262 

use   of 118 

West  Coast  Calcimine  Company 52 

M''est  Coast  Porcelain    IVIanufacturers    215 

"West  Coast  Tile    Company    95 

Western  Brick  Company 122 

clay,   Santa  Monica 102 

Westinghouse   Electric  and   Manufacturing  Company 30,     45 

Weston,   A.    M.    189 


INDEX  383 

ragf 

Weston,    r'aul    208 

West  ViiHiiiia  Ceological  Survey     237 

W  li.atlaiid    23G 

\\  hiskjv    Hill    Mine    iaec  Valley   View   Mine). 

\\  liisl.r,   C.    .M.    45 

Wliite-huining  clays,  tests  of 257-276 

\\  liiteware,  clays  suitable  for 253,  254 

Wliitiker,  10.  H 218 

WhitiiiK-Mfad   Company    123 

WiU-ox,  Ralph 208 

Wild,   G.  A. 122 

Wildomar 180 

Willow   Creek   192 

Willows 79 

Wilson,  Prof.  Hewitt 13,  246,  262,  257,  262 

Wilson,  J.  M. 181 

I  lay    181 

tests  of   (No.  42-43) 340 

Wilson.   L.   H. 97 

Windsor    227 

Winters 235 

Wiro  Mine   (see  Vitrified  Products  Corporation). 

Wolf    137,  138 

Woodland     235 

Woolenius  Tiles 49 

Worthington,   R.   L. 94 

Wretman,   X.   E. 220 

Wrights    220 

Y 

Yankee  Hill 66 

Yaru  pit   (lone)   56 

clays,  tests  of 302,  335 

Yellow  ware,  clays  suitable  for 255 

Y'olo   County    234 

clay  resources 235 

bibliography    235 

Yosemite  I'ortland  Cement  Company 63 

Yost,   A.    D.    140 

Yreka    224 

Yuba    County    235 

clay  resources 235 

geology 235 

Yuba  Well   84 

Z 
Zabri.skie 88 

Zinc  retorts,  clays  suitable  for ; 253,  254,  255 


O 


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